Method and apparatus for synchronizing a smart antenna apparatus with a base station transceiver

ABSTRACT

A method of synchronizing a smart antenna apparatus with a base station transceiver includes receiving at the smart antenna apparatus control signals being communicated from a base station transceiver to one or more mobile stations via an antenna unit. The control signals are operable to be used to synchronize the mobile stations with the base station transceiver. The method further includes executing one or more algorithms using the control signals received by the smart antenna apparatus as input to synchronize the smart antenna apparatus with the base station transceiver.

TECHNICAL FIELD OF THE INVENTION

This invention relates generally to the field of wireless communicationssystems and, more specifically, to a method and apparatus forsynchronizing a smart antenna apparatus with a base station transceiverin time and/or frequency.

BACKGROUND OF THE INVENTION

The rising use of mobile communications systems has led to an increasingdemand for enhancing efficiency and performance characteristics, such asincreasing network capacity, data rate, signal quality, networkcoverage, and power efficiency. When a wireless signal is transmitted toa receiver, such as an antenna, the receiver often receives interferencealong with the signal, making it difficult for the receiver to determinethe original signal. This interference may include interference causedby the multipath phenomenon and/or co-channel interference caused byother signals or random noise in the same frequency as the originalsignal. Smart antenna (SA) systems are designed to reduce these types ofinterferences, and thus enhance the performance characteristicsdiscussed above.

A smart antenna system is generally located near a base stationtransceiver and combines an array of antenna elements with digitalsignal processing capabilities to receive and transmit signals in aspatially sensitive manner. In other words, a smart antenna can adaptthe direction of transmissions in response to the signals it receives.Thus, a smart antenna system may be said to track, or follow, mobilecommunication devices (such as mobile phones or personal digitalassistants) as they change their location or active status (such asidle, ready, or standby). For example, when a mobile user is located ina particular location within a sector, the smart antenna system mayselect a best beam that provides the best coverage for that location andtransmit signals to and receive signals from the mobile through thatbest beam. As the user moves to new locations, the smart antenna systemmay adapt by switching to the beam or beams that provide the bestcoverage for those locations.

SUMMARY OF THE INVENTION

In accordance with the present invention, a method and apparatus forsynchronizing a smart antenna apparatus with a base station transceiverin time and frequency are provided that substantially eliminate orreduce the disadvantages and problems associated with previouslydeveloped methods and apparatuses.

In one embodiment of the present invention, a method of synchronizing asmart antenna apparatus with a base station transceiver is provided. Themethod includes receiving at the smart antenna apparatus control signalsbeing communicated from a base station transceiver to one or more mobilestations via an antenna unit. The control signals are operable to beused to synchronize the mobile stations with the base stationtransceiver. The method further includes executing one or morealgorithms using the control signals received by the smart antennaapparatus as input to synchronize the smart antenna apparatus with thebase station transceiver.

In another embodiment, a smart antenna apparatus is provided. The smartantenna apparatus includes a signal receiver operable to receive one ormore control signals being communicated from a base station transceiverto one or more mobile stations via an antenna unit. The control signalsare operable to be used to synchronize the mobile stations with the basestation transceiver. The smart antenna apparatus further includes aprocessor operable to execute one or more synchronization algorithmsusing the control signals received at the signal receiver as input tosynchronize the smart antenna apparatus with the base stationtransceiver.

Various embodiments of the present invention may benefit from numeroustechnical advantages. It should be noted that one or more embodimentsmay benefit from all, some, or none of the advantages discussed below.

One technical advantage includes a smart antenna apparatus that may beaccurately synchronized with a base station transceiver using controlsignals received from the base station transceiver via radio signalwires. The smart antenna apparatus may include a processing systemoperable to execute one or more synchronization algorithms, using thecontrol signals (which include synchronization signals) as input, tosynchronize the smart antenna apparatus with the base stationtransceiver in time and frequency with a high degree of accuracy. Inaddition, the smart antenna apparatus may be synchronized with the basestation transceiver more accurately than mobile stations aresynchronized with the base station transceiver using the samesynchronization signals over an air channel. This may allow the smartantenna apparatus to properly perform its various functions, such asbeam-switching operations.

Another technical advantage is that the smart antenna apparatus may besynchronized with the base station transceiver using control signalsreceived from the base station transceiver without affecting thecommunication of the radio signals from the base station transceiver toan antenna unit for transmission to one or more mobile stations.

Another technical advantage is that the smart antenna apparatus may beadded to an existing base station transceiver as an add-on or appliquewithout requiring modifications to the base station transceiver. This ispossible since the smart antenna apparatus is synchronized with the basestation transceiver via signals communicated through radio signal wireswhich may be coupled directly to a base station transceiver withoutmodifying the base station transceiver. Thus, the cost and labor ofmodifying or altering the base station transceiver and/or dealing ornegotiating with the manufacturer of the base station transceiver isreduced or eliminated.

Other technical advantages are readily apparent to one skilled in theart from the following figures, descriptions, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the invention, and for furtherfeatures and advantages, reference is now made to the followingdescription, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 illustrates a wireless communication system including a smartantenna system and a base station in accordance with an embodiment ofthe present invention;

FIG. 2 illustrates the general architecture and operation of the smartantenna system of FIG. 1 including a smart antenna apparatus and anantenna unit;

FIG. 3 illustrates a receiving system of the smart antenna apparatus ofFIG. 2;

FIG. 4 illustrates a processing system of the smart antenna apparatus ofFIG. 2;

FIG. 5 illustrates a system for monitoring control signals beingcommunicated from a base station transceiver to mobile stations andsynchronizing the smart antenna apparatus with the base stationtransceiver using the control signals in accordance with an embodimentof the present invention;

FIG. 6 illustrates a method for monitoring control signals beingcommunicated from a base station transceiver to mobile stations inaccordance with an embodiment of the present invention;

FIG. 7 illustrates a method for synchronizing the smart antennaapparatus with the base station transceiver during start-up inaccordance with an embodiment of the present invention;

FIG. 8 illustrates a method for maintaining the smart antenna apparatusin synchronization with the base station transceiver during steady-stateoperation in accordance with an embodiment of the present invention;

FIG. 9 illustrates a system for monitoring signaling information beingcommunicated via an interface between a base station transceiver and abase station controller in accordance with an embodiment of the presentinvention;

FIG. 10 illustrates a method for monitoring signaling information beingcommunicated via the interface illustrated in FIG. 9;

FIG. 11 illustrates a system for determining beam selections with thesmart antenna apparatus of FIG. 2;

FIG. 12 illustrates a system for determining fast decision beamselections in accordance with an embodiment of the present invention;

FIG. 13 illustrates a method for determining fast decision beamselections in accordance with an embodiment of the present invention;

FIG. 14 illustrates a system for controlling the gain settings for eachbeam receiver for determining fast decision beam selections inaccordance with an embodiment of the present invention;

FIG. 15 illustrates a method for controlling the gain settings for eachbeam receiver for determining fast decision beam selections inaccordance with an embodiment of the present invention;

FIG. 16 illustrates a system for determining smart decision beamselections including a smart decision beam selection module inaccordance with an embodiment of the present invention;

FIG. 17 illustrates the architecture and operation of the smart decisionbeam selection module of FIG. 16 in accordance with an embodiment of thepresent invention;

FIG. 18 illustrates a method for determining smart decision beamselections in accordance with an embodiment of the present invention;

FIG. 19 illustrates a correlation module for determining a correlationquality of each uplink beam for use in determining smart decision beamselections in accordance with an embodiment of the present invention;

FIG. 20 illustrates a method for determining a correlation qualityuplink beams by correlating a signal sequence in each uplink beam withone or more known training sequences in accordance with an embodiment ofthe present invention;

FIG. 21 illustrates a method for determining a correlation qualityuplink beams by correlating a signal sequence in each uplink beam withone or more known training sequences in accordance with an embodiment ofthe present invention;

FIG. 22 illustrates a system for determining whether to use a fastdecision beam selection or a smart decision beam selection for aparticular time slot in accordance with an embodiment of the presentinvention; and

FIG. 23 illustrates a method for determining whether to use a fastdecision beam selection or a smart decision beam selection for aparticular time slot in accordance with an embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE DRAWINGS

Example embodiments of the present invention and their advantages arebest understood by referring now to FIGS. 1 through 23 of the drawings,in which like numerals refer to like parts.

Generally, a smart antenna system is provided as an add-on to anexisting base station in a wireless communications system. The smartantenna system combines an antenna unit that may include a smart antennaarray and optionally a backup sector antenna with a smart antennaapparatus having signal processing capabilities to receive and transmitsignals in a spatially sensitive manner, or in other words, along one ormore selected beams. The smart antenna apparatus is operable to executeone or more algorithms, based on a number of inputs, to select an uplinkbeam for uplink signals and a downlink beam for downlink signals. Theuplink beam is used to communicate uplink signals received from a mobilestation to a base station transceiver. The downlink beam is used tocommunicate downlink signals from the base station transceiver to themobile station.

The smart antenna apparatus may include a fast decision beam selectionmodule to make beam selections in substantially real time and a smartdecision beam selection module to make beam selections based on moreinput and processing. The smart antenna apparatus may be operable todetermine whether to use the results from the fast decision beamselection module or the smart decision beam selection module dependingon the particular circumstances. In general, the smart antenna apparatusmay use the fast decision beam selection module to make beam selectionsduring the initiation of a call from a mobile station and then switch tothe smart beam selection module after the call is established.

The smart antenna system may collect and use signaling information formaking beam selection determinations generally as follows. The basestation transceiver and the base station controller communicatesignaling and traffic information with each other via an interface, suchas an A-bis interface in a GSM or GPRS environment or an LUB interfacein a 3G environment. The smart antenna apparatus includes a monitoringsystem coupled to the signaling interface and operable to receivesignaling information being communicated between the base stationtransceiver and the base station controller without affecting, ordisturbing, the communication of the signaling or traffic informationbetween base station transceiver and the base station controller. Thesignaling information received by the monitoring system may then bedecoded, filtered and/or otherwise processed to determine relevantsignaling information for the smart antenna apparatus. The relevantsignaling information may be used by a smart antenna processing systemin selecting uplink and/or downlink beams.

In addition, the smart antenna apparatus may also be operable tosynchronize itself with the base station transceiver in time andfrequency using control channel signals being communicated from the basestation transceiver to one or more mobile stations. The smart antennaapparatus may include a control channel monitoring module operable toconvert control channel signals received from the base stationtransceiver in a downlink frequency to a frequency that may be receivedby a smart antenna receiver. A processing module may execute one or moresynchronization algorithms using the control channel signals as input inorder to synchronize the smart antenna apparatus with the base stationsystem in time and frequency.

The smart antenna apparatus may be coupled to the existing base stationas an applique with little or no modification needed to be made to anycomponent of the base station, including the base station transceiver.In particular, the signaling information monitoring system is operableto passively monitor the signaling information being communicatedbetween the base station controller and the base station transceiverwithout making any modifications to the base station controller or thebase station transceiver. In addition, the control channel monitoringmodule is operable to passively monitor the control channel informationbeing communicated from the base station transceiver to the mobilestations without making any modifications to the base stationtransceiver. Thus, the smart antenna apparatus may be easily andinexpensively coupled to a variety of existing base stations.

FIG. 1 illustrates an embodiment of a wireless communication system 10that includes a base station system 12, a smart antenna system 14, andone or more mobile stations 15. In one embodiment, wirelesscommunication system 10 operates in a GSM (Global System for MobileCommunications) environment. However, wireless communication system 10may operate according to other wireless standards including, forexample, CDMA (Code Division Multiple Access) standards such as IS-95Aand IS-95B, CDMA 2000, W-CDMA, TD SCDMA, TETRA, and TDMA (Time DivisionMultiple Access) standards such as IS-136 and IS-54, without departingfrom the scope of the present invention.

Base station system 12 may include one or more base station transceivers24, a base station controller 26, and any other suitable components of awireless communications base station. Smart antenna system 14 mayinclude an antenna unit 18 and a smart antenna apparatus 16. Smartantenna apparatus 16 may be coupled to base station system 12 as anadd-on or an applique.

Base station transceiver 24 is generally operable to communicate radiosignals to and from antenna unit 18 via one or more radio signal wires40 and 42. In this manner, base station transceiver 24 is operable totransmit radio signals to and receive radio signals from one or moremobile stations 15 via antenna unit 18. Base station controller 26 isgenerally operable to control the operation of one or more base stationtransceivers 24.

Base station controller 26 and base station transceiver 24 may becoupled by an interface 36. Interface 36 may be operable to communicatesignals, including traffic and control (or signaling) information,between base station controller 26 and base station transceiver 24, asdescribed in greater detail with reference to FIG. 9.

In a GSM (Global System for Mobile Communications) environment, basestation system 12 may be a Base Station System (BSS), base stationtransceiver 24 may be a Base Transceiver Station (BTS) and base stationcontroller 26 may be a Base Station Controller (BSC). In athird-generation (3G) environment (such as W-CDMA or CDMA 2000, forexample), base station system 12 may be a Radio Network Server (RNS),base station transceiver 24 may be a Node B base station, and basestation controller 26 may be a Radio Network Controller (RNC). Basestation system 12, base station transceiver 24, and base stationcontroller 26 may alternatively be any other suitable base stationcomponents in other wireless communication environments or underdifferent communication standards.

Antenna unit 18 may include a smart antenna array 28 including aplurality of antenna elements 30. Antenna unit 18 may also include asector antenna 31 operable to transmit and/or receive signals throughouta sector. In some embodiments, sector antenna 31 is comprised of one ormore antenna elements similar to antenna elements 30 in smart antennaarray 28. In the embodiment shown in FIG. 1, antenna unit 18 is locatedon an antenna tower 22. However, antenna unit 18 may be otherwiselocated, for example on a building. Preferably, signals directed to andfrom antenna unit 18 are generally unobstructed near antenna unit 18, orin other words, antenna elements 30 can “see” a large area.

Traditional sector antennas used in cellular communication systemstransmit radio signals in a wide beam to a relatively wide area, orsector, since the location of mobile stations is unknown to the system.Such systems pollute the electromagnetic environment by transmittingsignals in unnecessary directions. In contrast, smart antenna system 14divides the wide beam into a plurality of narrow beams. For example, inthe embodiment shown in FIG. 1, smart antenna system 14 divides a widebeam 32 covering an approximate 120 degree range into seven narrow beams34. This is accomplished by manipulating the phase of the signalsreceived by antenna elements 30 of smart antenna array 28. In someembodiments, narrow beams 34 are formed using a beamforming network,sometimes referred to as a BFN. In contrast, sector antenna 31 transmitsand receives signals throughout the sector through wide beam 32,bypassing the beamforming network. Signals may be communicated betweenantenna unit 18 and a particular mobile station 15 via a narrow beam 34or via wide beam 32 (using sector antenna 31), depending on variousparameters.

Antenna unit 18 may be coupled to smart antenna apparatus 16 by one ormore radio signal wires 40 operable to communicate radio signals betweenantenna unit 18 and smart antenna apparatus 16. For example, antennaunit 18 may be coupled to smart antenna apparatus 16 by a plurality ofradio signal wires 40, each corresponding to a narrow beam 34.Similarly, smart antenna apparatus 16 may be coupled to base stationtransceiver 24 by one or more radio signal wires 42 operable tocommunicate radio signals between smart antenna apparatus 16 and basestation transceiver 24. Radio signal wires 40 and 42 may include anywire media suitable for communicating radio frequency signals. Forexample, in one embodiment, radio signal wires 40 and 42 are radiofrequency (RF) cables.

When a mobile station 15 transmits uplink signals, the uplink signalsmay be received along any number of narrow beams 34 due to multi-path orother interference phenomena, and/or due to overlapping areas covered byadjacent narrow beams 34. The uplink signals received via each narrowbeam 34 are communicated to smart antenna apparatus 16 via radio signalwires 40. In one embodiment, one or more separate radio signal wires 40are provided to communicate the signals received via each narrow beam34.

Smart antenna apparatus 16 processes uplink signals received along eachnarrow beam 34 and/or other input signals or data to select the bestnarrow beam 34 and to allow uplink signals received via that narrow beam34 to be communicated to base station transceiver 24 via radio signalwires 42. For example, smart antenna apparatus 16 may select the bestnarrow beam 34 based on one or more inputs or parameters. One input mayinclude signaling information received by signaling informationmonitoring system 106 (described below in connection with FIG. 2). Otherexample inputs or parameters include signal strength, signal quality,relevant power, and signal history of signals received from one or moremobile stations 15. After smart antenna apparatus 16 communicates theuplink signals received via the selected narrow beam 34 to base stationtransceiver 24, the uplink signals may be processed and/or furthercommunicated by base station system 12. It should be noted that the term“narrow beam” as used in this document applies both to the physicalbeams through which antenna unit 18 transmits and receives signals (asindicated using reference numeral 34 in FIG. 1) as well as the signalsreceived via each of the physical beams.

When downlink signals are to be transmitted from base station system 12to mobile station 15, the downlink signals are communicated from basestation transceiver 24 to smart antenna apparatus 16 via radio signalwires 42. Smart antenna apparatus 16 may select a best narrow beam 34through which to send the downlink signals. Like the beam selection foruplink signals discussed above, the beam selection for the downlinksignals may be based on one or more inputs or parameters, includingsignaling information received by signaling information monitoringsystem 106. Other example inputs or parameters include signal strength,signal quality, and signal history of signals received from one or moremobile stations 15.

Smart antenna apparatus 16 may switch from one narrow beam 34 to anothernarrow beam 34 accordingly. For example, when mobile station 15 moves toa new location, smart antenna system 14 may switch from one narrow beam34 to another narrow beam 34 for receiving uplink signals from and/ortransmitting downlink signals to mobile station 15. In this manner,smart antenna system 14 may locate and track mobile stations 15 as theymove within wide beam 32, and transmit signals to and receive signalsfrom each mobile stations 15 via one or more appropriate narrow beams34. At a particular point in time, the narrow beam 34 selected as thebest beam for communicating uplink signals received from mobile station15 to base station transceiver 24 may be the same as, or different from,the narrow beam 34 selected as the best beam for communicating downlinksignals to mobile station 15. This may provide an advantage insituations in which the best beam for receiving uplink signals from amobile station is not the same as the best beam for transmitting signalsto that mobile station. This may be likely, for example, inhigh-interference environments, such as dense or urban environments.

Base station system 12 may communicate with mobile stations 15 within arange of frequencies, which may be divided into a number of frequencybands. According to some wireless communication standards, the availablebandwidth is divided into a number of frequency bands, which may each bereferred to simply as a frequency. In some standards, each uplinkfrequency (in other words, a frequency used for uplink communications)may be associated with a corresponding downlink frequency, such thatpairs of frequencies are available. For example, in a P/E/R-GSM 900environment, each frequency (both uplink and downlink) has a bandwidthof 200 kHz, and each uplink frequency band is offset from itscorresponding downlink frequency band by 45 MHz. Typically, due tolimitations of signal interference and cost, only a portion of thefrequencies available in a particular environment are used by anyparticular base station transceiver. For example, in one embodiment,four pairs of uplink and downlink frequencies are to be used by eachbase station transceiver. It should be noted that in other standards,such as the TD-SCDMA standard, one frequency is used for both uplink anddownlink communications.

In a GSM environment, signals may be communicated in differentfrequencies over a period of time, which is divided into frames that areeach divided into eight time slots, or channels. Each time slot, orchannel, is either a control channel or a traffic channel. Controlchannels are operable to carry control signals and/or signaling orpaging signals, while traffic channels are operable to carry voiceand/or other data signals. In the GSM standard, one of the eightchannels in a particular frequency, which may be referred to hereinafteras the control frequency, is designated as the control channel. Theremaining channels in the control frequency may be traffic channelsoperable to carry conversations. The control frequency thus consists ofone control channel and seven traffic channels. Each remaining frequencymay be referred to as a traffic frequency consisting of eight trafficchannels. Generally, each traffic channel can support one conversationor other communication in full rate, two conversations or othercommunications in half rate, or an unlimited number of conversations orother communications in GPRS or group mode.

When a particular mobile station 15 is engaged in a call, voice and/orother data signals intended for that mobile station 15 are transmittedfrom base station system 12 via smart antenna array 28 within aparticular traffic channel (or time slot) in a particular frequency. Themobile station 15 will “listen” for the voice and/or data signals onlyin the particular traffic channel in the particular frequency. Thus,mobile station 15 must know when, and at which frequency, to “listen”for the voice signals, and thus must be synchronized to base stationtransceiver 24.

Smart antenna apparatus 16 must also be synchronized with base stationtransceiver 24 in order to operate properly. For example, smart antennaapparatus 16 must be synchronized with base station transceiver 24 inorder to perform its beam-switching functions as discussed above.Further, in some embodiments, smart antenna apparatus 16 should besynchronized with base station 12 more accurately than mobile station 15is synchronized with base station 12. The synchronization of smartantenna apparatus 16 with base station 12 is discussed in greater detailbelow with reference to FIGS. 5 through 8.

FIG. 2 illustrates the general architecture and operation of smartantenna system 14. As discussed above, smart antenna system 14 includessmart antenna apparatus 16 and antenna unit 18. Smart antenna apparatus16 includes a receiving system 100, a processing system 102, a storagesystem 103, a control channel monitoring module 104, and a signalinginformation monitoring system 106. In some embodiments, smart antennaapparatus 16 also includes one or more diplexers, such as diplexers 120and 122.

Receiving system 100 is generally operable to receive radio signalscommunicated from mobile stations 15. In particular, receiving system100 may receive analog radio signals communicated from mobile stations15, received at antenna unit 18, and communicated to receiving system100 via paths 151 and 152. Receiving system 100 may be further operableto convert the analog radio signals to digital signals and communicatethe digital signals to processing system 102.

As shown in FIG. 3, receiving system 100 may include one or morefrequency receiver units 108, each corresponding with a particularfrequency (in other words, a frequency band) and thus operable toreceive signals communicated by mobile stations 15 via that frequency.Each frequency receiver unit 108 may include one or more beam receivers112 operable to receive signals communicated in a particular frequency.Each frequency receiver unit 108 may include a beam receiver 112corresponding with each narrow beam 34. For example, in one embodimentin which smart antenna system 14 divides wide beam 32 into seven narrowbeams 34, each frequency receiver unit 108 includes eight beam receivers112, one for each of the seven narrow beams 34 and one for wide beam 32,which is received by sector antenna 31. Beam receivers 112 may beoperable to convert received radio frequency signals into basebandsignals. In a particular embodiment, the beam receivers 112 areidentical to each other.

Receiving system 100 may also include one or more samplers 116 operableto convert signals from analog to digital. In particular, one or moresamplers 116 may convert analog signals received by each beam receiver112 to digital signals such that the signals may be processed byprocessing system 102.

Referring again to FIG. 2, processing system 102 is generally operableto perform beam-selection functions. In particular, processing system102 may execute one or more algorithms based on various inputs and/orparameters to determine a transmitting beam selection 124 and areceiving beam selection 126. In other words, processing system 102 isoperable to select one of the narrow beams 34 to communicate signalsreceived by antenna unit 18 to base station transceiver 24, and one ofthe narrow beams 34 (which may be the same or a different narrow beam34) to transmit downlink signals to mobile stations 15.

As shown in FIG. 4, processing system 102 may include one or moreprocessing modules 62 operable to process received signals, such assignaling signals, control signals, and/or traffic signals. In someembodiments, processing system 102 includes one processing module 62 foreach frequency used by smart antenna system 14. Thus, each processingmodule 62 may process signals communicated in one of the frequenciesused by base station transceiver 24. Each processing module 62 isgenerally operable to perform one or more functions, includingbeam-selection functions. In an environment using time divisionmuliplexing, such as a GSM environment, each processing module 62 may beoperable to determine both uplink and downlink beam selections forcommunicating signals in each time slot. Thus, in some embodiments, eachprocessing module 62 is operable to determine both uplink and downlinkbeam selections for each time slot in a particular frequency.

Processing modules 62 may make beam selection decisions based on one ormore inputs or parameters, including signals received from receivingsystem 100 and/or signaling information received from signalinginformation monitoring system 106. For example, each processing module62 may be operable to execute one or more beam-selection algorithms tomake beam selection determinations. In one embodiment, each processingmodule 62 is operable to execute a fast decision beam-selectionalgorithm or a smart decision beam-selection algorithm based on one ormore parameters, such as whether the processor has knowledge of thenumber and/or location of mobile stations 15 using the frequencycorresponding with that processing module 62.

One or more processing modules 62 may also be operable to synchronizesmart antenna apparatus 16 with base station transceiver 24 in timeand/or frequency. In particular, one or more processing modules 62 maybe operable to execute one or more synchronization algorithms usingcontrol signals, including synchronization signals, received fromcontrol channel monitoring module 104 to synchronize smart antennaapparatus 16 with base station transceiver 24.

Processing system 102 may also include a central processing unit, suchas host processor 118, operable to further process the output of eachprocessing module 62. In one embodiment, host processor 118 is operableto determine errors or whether the outputs of one or more processingmodule 62 are valid or require modification.

Each processing module 62 may include one or more processors 63, such asmicroprocessors, digital signal processors, or any other type ofprocessors capable of executing an algorithm. In one embodiment, eachprocessing module 62 includes one or more programmable digital signalprocessors. Although processing system 102 as described above includesdiscrete processing modules 62 for processing signals at differentfrequencies or for performing different functions, it should beunderstood that the processing functions performed by smart antennasystem 14 may be performed by any appropriate number and combination ofprocessing modules 62.

Referring again to FIG. 2, storage system 103 is operable to storeinformation or data for use by smart antenna apparatus 16. Inparticular, storage system 103 may store information received fromsignaling information monitoring system 106. Storage system 103 may alsobe operable to provide information to and receive information fromprocessing system 102.

Control channel monitoring module 104 is generally operable to receivecontrol channel signals, including synchronization signals, beingcommunicated from base station transceiver 24 to antenna unit 18, and toprepare such signals to be processed by processing system 102. In someembodiments, control channel monitoring module 104 is operable to filterand convert the control channel signals from a base station transmittingfrequency to a smart antenna receiving frequency, receive and sample thesignals, and communicate the signals to processing system 102. Thecontrol channel signals, including the synchronization signals, may thenbe processed by processing system 102 in order to synchronize smartantenna apparatus 16 with base station transceiver 24, as discussed ingreater detail below with reference to FIGS. 5 through 8.

Signaling information monitoring system 106 is generally operable tomonitor, or receive, signaling information (in other words, base stationcontrol information) being communicated between base station transceiver24 and base station controller 26 via interface 36. Signalinginformation monitoring system 106 may also be operable to extract asubset of relevant information from the received signaling informationto communicate to processing system 102 as an input in makingbeam-selection determinations. The relevant information may includeinformation related to one or more mobile stations 15, such as frequencyhopping, for example. The systems and methods for monitoring thesignaling information are discussed in greater detail below withreference to FIGS. 9 and 10.

The various systems and modules of smart antenna apparatus 16, includingreceiving system 100, processing system 102, control channel monitoringmodule 104, and signaling information monitoring system 106, as well asthe components of each system and module, may or may not be co-located,and may be divided and/or combined in any appropriate manner. Forexample, smart antenna apparatus 16 may include a ground unit located onor near the ground and a tower unit coupled to antenna tower 22. In oneembodiment, smart antenna apparatus 16 includes a ground unit located onthe ground and a tower unit located near the top of antenna tower 22proximate antenna unit 18. In another embodiment, smart antennaapparatus 16 includes a ground unit and a tower unit both located on ornear the ground. In another embodiment, smart antenna apparatus 16includes only one unit such that the components of smart antennaapparatus 16 are generally co-located.

As shown in FIG. 2, antenna unit 18 may include antenna array 28comprising antenna elements 30, as well as a beam forming network (BFN)128. Beam forming network 128 is operable to form a plurality of uplinkbeams 150, each corresponding with, and communicating signals receivedvia, one of the narrow beams 34 by controlling the amplitude and phaseof signals received by antenna elements 30. In one embodiment, beamforming network 128 forms seven uplink beams 150.

In operation, uplink analog signals are communicated by one or moremobile 5 stations 16 via one or more narrow beams 34 and received byantenna array 28. Beam forming network 128 forms a plurality of uplinkbeams 150 and communicates uplink beams 150 to smart antenna apparatus16. Uplink beams 150 are received by receiving system 100. In oneembodiment in which smart antenna apparatus 16 includes diplexer 122,uplink beams 150 are received by receiver system 100 after passingthrough diplexer 122. Each uplink beam 150 may be received by a separatefrequency receiver unit 108. Each beam may then be converted from analogto digital by a sampler 116.

The digital uplink beams 150 are then communicated to processing system102. Using the received uplink beams 150, signaling information receivedfrom signaling information monitoring system 106, and/or otherparameters as input, processing system 102 executes one or morebeam-selection algorithms to determine a receiving beam selection 126corresponding to one of the uplink beams 130. The receiving beamselection 126 is communicated to a receiving beam switch 127 whichfilters the uplink beams 150 received from beam forming network 128 suchthat only the uplink beam 150 corresponding to the receiving beamselection 126 may pass through to base station transceiver 24. In oneembodiment in which smart antenna apparatus 16 includes diplexer 120,the uplink beam 130 is received by base station transceiver 24 afterpassing through diplexer 120.

In particular, each processing module 62 may execute one or morebeam-selection algorithms to determine a receiving beam selection 126for each frequency used by smart antenna system 14. In addition, in atime division multiplexing environment, such as a GSM environment, eachprocessing module 62 may determine a receiving beam selection 126 foreach time slot in each frequency.

In one embodiment, each processing module 62 determines a receiving beamselection 126 by determining a fast decision beam selection using a fastdecision beam selection module and/or a smart decision beam selectionusing a smart decision beam selection module. The processing module 62may determine whether to use the fast decision beam selection or thesmart decision beam selection as the receiving beam selection 126 basedon one or more parameters, such as whether the processor has priorknowledge of a particular mobile stations 15.

In some embodiments, the fast decision beam selection module is operableto determine the receiving beam selection 126 in real time. In otherwords, the fast decision beam selection module is operable to determinea fast decision beam selection based on signals communicated via eachuplink beam 130 in a first portion of a particular time slot, andreceiving beam switch 127 is operable to switch to the fast beamselection in real time such that signals communicated via the selecteduplink beam 130 in a subsequent portion of the same time slot may passthrough receiving beam switch 127 to base station transceiver 24.

In contrast, the smart decision beam selection module may determine thereceiving beam selection 126 to be used by receiving beam switch 127 inlater time slots or frames. For example, in one embodiment, the smartdecision beam selection module determines a smart decision beamselection based on the signals received in the current time slot and oneor more previous time slots, but receiving beam switch 127 does notswitch to the smart decision beam selection until the following frame.Thus, in this embodiment, receiving beam switch 127 may switch to theuplink beam 130 corresponding with the smart decision beam selection inthe frame following the last frame used in determining the smartdecision beam selection.

Downlink signals are communicated from base station transceiver 24 to betransmitted to one or more mobile stations 15 via antenna unit 18. Thedownlink signals are received by smart antenna apparatus 16 and adownlink beam 132 corresponding with one of the narrow beams 34 isselected for communicating the downlink signals to the mobile stations15. In one embodiment in which smart antenna apparatus 16 includesdiplexer 120, the downlink signals pass through diplexer 120 beforebeing assigned to a narrow beam 34.

A transmitting beam switch 125 is operable to assign the downlinksignals to a downlink beam 132 based on a transmitting beam selection124 determined by processing system 102. The same or similar inputsand/or parameters used to determine receiving beam selection 126 may beused by processing system 102 to determine transmitting beam selection124. The downlink signals are assigned to the downlink beam 132corresponding to the transmitting beam selection 124 and the downlinkbeam 132 is communicated to antenna unit 18 and transmitted through thecorresponding narrow beam 34. In one embodiment in which smart antennaapparatus 16 includes diplexer 122, the downlink beam 132 is received byantenna unit 18 after passing through diplexer 122.

As with the uplink beam selection, each processing module 62 may executeone or more beam-selection algorithms to output a transmitting beamselection 124 for each frequency used by smart antenna system 14. Inaddition, in a time division multiplexing environment, such as a GSMenvironment, each processing module 62 may determine a transmitting beamselection 124 for each time slot in each frequency. At any particulartime, the transmitting beam selection 124 for a particular downlinkchannel may or may not be the same as the receiving beam selection 126determined for the corresponding uplink channel. In other words, thenarrow beam 34 corresponding with the uplink beam 130 selected forcommunicating uplink signals from a mobile station 15 to base stationtransceiver 24 may not always be the same narrow beam 34 selected forcommunicating downlink signals from base station transceiver 24 to thatmobile station 15. In addition, as with the receiving beam selection,each processing module 62 may determine a transmitting beam selection124 by determining a fast decision beam selection using a fast decisionbeam selection module and/or a smart decision beam selection using asmart decision beam selection module.

As discussed above, the inputs used by processing system 102 in makingbeam selection determinations may include signaling information receivedfrom signaling information monitoring system 106. In operation,signaling information monitoring system 106 monitors, or receives,signaling information being communicated between base stationtransceiver 24 and base station controller 26 via interface 36.Signaling information monitoring system 106 extracts relevantinformation from the received signaling information and communicatesthis information to processing system 102 as an input for making beamselections. The systems and methods for monitoring the signalinginformation are discussed in greater detail below with reference toFIGS. 9 and 10.

Processing system 102 is synchronized and kept in synchronization withbase station transceiver 24 using control signals received from controlchannel monitoring module 104. In operation, control channel monitoringmodule 104 receives, or monitors, control channel signals (includingsynchronization signals) being communicated from base stationtransceiver 24 to antenna unit 18. Control channel monitoring module 104filters and converts the control channel signals from a base stationtransmission frequency to an smart antenna receiving frequency, receivesand samples the signals, and communicate the signals to processingsystem 102. Processing system 102 uses the signals to synchronize itselfwith base station transceiver 24 in time and frequency. Processingsystem 102 may execute one or more synchronization algorithms using thecontrol channel signals as input to synchronize itself with base stationtransceiver 24. The system and method of synchronization is discussed indetail below with reference to FIGS. 5 through 8.

FIGS. 5 through 8 illustrate example systems and methods for accuratelysynchronizing smart antenna apparatus 16 with base station transceiver24 in time and frequency. In general, smart antenna apparatus 16 usesthe same synchronization signals that are used by mobile station 15 tosynchronize mobile station 15 with base station transceiver 24. In oneembodiment, the synchronization signals are obtained by smart antennaapparatus 16 from the radio signals being communicated from base stationtransceiver 24 to antenna unit 18 via radio signal wires 42 and 40. Thepath of the radio signals transmitted from base station transceiver 24may be split at smart antenna apparatus 16 such that one path is used tosynchronize smart antenna apparatus 16 with base station transceiver 24and another path continues to, and is transmitted by, antenna unit 18 inorder to synchronize mobile stations 15 with base station transceiver24.

In this manner, smart antenna apparatus 16 may be synchronizedaccurately with base station transceiver 24 using the radio signalscommunicated from base station transceiver 24 via radio signal wires 40.Thus, in some embodiments, the components of base station system 12,including base station transceiver 24, do not need to be modified,altered, or reconfigured in order for smart antenna apparatus 16 to besynchronized with, and maintained in synchronization with, base stationtransceiver 24. In one embodiment, smart antenna apparatus 16 may besynchronized accurately with base station transceiver 24 using onlysignals received from base station transceiver 24 via radio signal wires42. Thus, the cost and labor of modifying or altering base stationsystem 12 and/or dealing or negotiating with the manufacturer of thecomponents of base station system 12, such as base station transceiver24, is reduced or, in some embodiments, eliminated.

In addition, smart antenna apparatus 16 may be synchronized accuratelywith base station transceiver 24 without interfering with the radiosignals being communicated from base station transceiver 24 and intendedfor mobile stations 15. This is accomplished by splitting the path ofthe radio signals communicated from base station transceiver 24 into afirst path directed toward antenna unit 18 for synchronizing mobilestations 15 and a second path directed toward a smart antenna receiverand processor for synchronizing smart antenna apparatus 16, as discussedbelow in greater detail.

FIG. 5 illustrates an embodiment of a base station transceiver 24, asmart antenna apparatus 16, and an antenna unit 18 for synchronizingsmart antenna apparatus 16 with base station transceiver 24. Smartantenna apparatus 16 includes a radio wire input 64, a splitter 50,control channel monitoring module 104, and processing module 62. Radiowire input 64 is operable to be coupled to one or more radio signalwires 42 to receive radio signals communicated from base stationtransceiver 24. In particular, radio wire input 64 may be operable toreceive signals communicated in a control channel, including controlsignals communicated within the control channel.

Splitter 50 is operable to split the path of a signal into two or morepaths. For example, splitter 50 may be a bi-directional or atri-directional coupler. In the embodiment shown in FIG. 5, splitter 50is a bi-directional coupler operable to divide an input path 66 of radiosignals received from radio wire input 64 into a first output path 68directed toward antenna unit 18 and a second output path 70 directedtoward first filter 52. Like input path 66, output paths 68 and 70 maybe operable to communicate signals received by radio wire input 64. Inaddition, splitter 50 may be operable to divide signal path 66 withoutinterfering with signals communicated from signal path 66 to signal path68. Thus, control channel monitoring module 104 may be operable topassively monitor, or receive, the control signals being communicatedfrom base station transceiver 24 to antenna unit 40. For example, thecontrol signals may be monitored without using active components. In oneembodiment, the control signals being communicated from base stationtransceiver 24 to antenna unit 40 are monitored without amplifying thecontrol signals.

In the embodiment shown in FIG. 5, control channel monitoring module 104comprises a first filter 52, a signal mixer 54, a second filter 56, areceiver 58, and a sampler 60. First filter 52 may include an attenuator72 and a bandpass filter 74. Attenuator 72 is operable to reduce theamplitude of radio signals by a predetermined amount without introducingdistortion to the signals. Bandpass filter 74 allows a specific band offrequencies to pass through while blocking or absorbing otherfrequencies outside the specified band. In one embodiment, bandpassfilter 74 allows the band of frequencies defined by the downlink controlfrequency to pass through, while blocking or absorbing otherfrequencies.

Signal mixer 54 is operable to mix, or combine, the signals receivedfrom first filter 52 with a conversion signal 76 in order to convert thesignals from one frequency to another frequency (in other words, fromone frequency band to another frequency band). Signal mixer 54 may beoperable to convert the signals from the downlink frequency at which thesignals were transmitted from base station transceiver 24 to thecorresponding uplink frequency at which the signal may be received byreceiver 58. For example, as discussed above, in the P/E/R-GSM 900standard, downlink frequencies are offset from their correspondinguplink frequencies by 45 MHz. Thus, as shown in FIG. 2, conversionsignal 76 may be approximately a 45 MHz signal such that signal mixer 54is operable to convert the signal from a downlink frequency to an uplinkfrequency which may be received by receiver 58. It should be understoodthat in some embodiments, conversion signal 76 is defined according tothe offset between downlink frequencies and corresponding uplinkfrequencies according to the particular communication environment. Forexample, in a GSM 850 environment, as in the P/E/R-GSM 900 environment,conversion signal 76 may be approximately a 45 MHz signal. In a GSM 1900environment, conversion signal 76 may be approximately an 80 MHz signal.In a GSM 1800 environment, conversion signal 76 may be approximately a95 MHz signal. In a GSM 480/450 environment, conversion signal 76 may beapproximately a 10 MHz signal.

Second filter 56 may include a receiving frequency bandpass filter 78and an attenuator 80. Like bandpass filter 74, bandpass filter 78 allowsa specific band of frequencies to pass through while blocking orabsorbing other frequencies outside the specified band. In oneembodiment, bandpass filter 78 allows the band of frequencies defined bythe corresponding uplink frequency to pass through, while blocking orabsorbing other frequencies. Like attenuator 72, attenuator 80 isoperable to reduce the amplitude of radio signals by a predeterminedamount without introducing distortion to the signals.

Receiver 58 is operable to receive signals from second filter 56 and isgenerally operable to receive radio signals within a particularfrequency band. In one embodiment, receiver 58 is operable to receivesignals within the uplink frequency bandwidth (in other words, thebandwidth of signals transmitted by mobile stations 15). In someembodiments, receiver 58 is similar or identical to other receivers usedby smart antenna apparatus 16 to receive radio signals from mobilestations 15, such as beam receivers 112. In a particular embodiment,receiver 58 is one of the beam receivers 112.

Sampler 60 is operable to convert signals from analog to digital.Sampler 60 may convert analog signals received by receiver 58 to digitalsignals such that the signals may be processed by processing module 62.

Processing module 62 is operable to process radio signals using one ormore synchronization algorithms 82. In one embodiment, processing module62 is operable to execute one or more synchronization algorithms 82using digital signals received from sampler 60 as input to synchronizesmart antenna apparatus 16 with base station transceiver 24 in time andfrequency. In the embodiment shown in FIG. 3, synchronization algorithms82 include a coarse timing synchronization algorithm 86, a framesynchronization algorithm 88, a fine timing synchronization algorithm90, and a fine frequency synchronization algorithm 92. Coarse timingsynchronization algorithm 86 and frame synchronization algorithm 88generally perform rough synchronizations, while fine timingsynchronization algorithm 90 and fine frequency synchronizationalgorithm 92 are generally fine tuning algorithms. These particularsynchronization algorithms 82 are discussed in greater detail below withreference to FIGS. 4 and 5. In one embodiment, processing module 62 isoperable to execute one or more synchronization algorithms 82 in orderto locate the control signals within the control frequency and to usecertain control signals, such as time and frequency synchronizationsignals, to synchronize smart antenna apparatus 16 with base stationtransceiver 24.

Base station transceiver 24 may include one or more radio wire outputs84 operable to receive one or more radio signal wires 42. Thus, smartantenna apparatus 16 may be coupled to base station transceiver 24 viaone or more radio signal wires 42.

FIG. 6 illustrates a method of synchronizing smart antenna apparatus 16with base station transceiver 24 using radio frequency control signalstransmitted by base station transceiver 24. Generally, base stationtransceiver 24 transmits radio signals via radio signal wires 42 in acontrol frequency intended for one or more mobile stations 15. Thecontrol frequency includes a control channel used to communicate controlsignals including synchronization signals. Smart antenna apparatus 16splits the path of the radio signals into a first path directed towardantenna unit 18 and a second path directed toward smart antenna receiver58 and processor 62. The radio signals are converted from a transmission(or downlink) frequency to a receiving (or uplink) frequency beforebeing received by receiver 58. Processor 62 executes one or moresynchronization algorithms using the radio signals (which include thecontrol signals) as input to synchronize smart antenna system 16 withbase station transceiver 24 in time and frequency with a high degree ofaccuracy. Thus, smart antenna system 16 may be accurately synchronizedwith base station transceiver 24 using radio signals received from basestation transceiver 24 via radio signal wires 42.

At step 200, downlink control frequency signals are communicated frombase station transceiver 24 via one or more radio signal wires 42. Thecontrol frequency signals are generally intended to be received by oneor more mobile stations 15 via wireless transmission, and may includecontrol signals within a control channel as well as voice signals withinone or more traffic channels. The control signals may includesynchronization data, such as time synchronization bursts and frequencysynchronization bursts, that may be used to synchronize mobile stations15 with base station transceiver 24 in time and/or frequency.

The downlink control frequency signals communicated from base stationtransceiver 24 are received at smart antenna apparatus 16 via the one ormore radio signal wires 42 at step 202. As shown in the embodiment ofFIG. 5, the signals are received by radio wire input 64. The signals arethen communicated through splitter 50 at step 204. The signals entersplitter 50 via signal path 66 which is divided by splitter 50 intofirst path 68 and second path 70. As discussed above, a first path 68 isdirected toward antenna unit 18 such that the downlink control frequencysignals, including control signals, may be communicated to mobilestations 15, and a second signal path 70 is directed toward first filter52 such that the downlink control frequency signals, including controlsignals, may be communicated to processing module 62.

Steps 206 through 212 illustrate the communication of the controlfrequency signals, in particular the control channel signals, fromsplitter 50 to mobile stations 15 for synchronizing mobile stations 15with base station transceiver 24. At step 206, the control frequencysignals are communicated from splitter 50 to antenna unit 18 via path 68which may include one or more radio signal wires 40. The signals arethen transmitted by antenna unit 18 at step 208. At step 210, thesignals are received by one or more mobile stations 15. Mobile stations15 use the control signals communicated in the control channel of thedownlink control frequency to synchronize themselves with base stationtransceiver 24 in time and/or frequency at step 212. Mobile stations 15may use one or more synchronization algorithms in order to synchronizethemselves with base station transceiver 24.

Steps 214 through 226 illustrate the communication of the downlinkcontrol frequency signals, in particular the control signals, fromsplitter 50 to processing module 62 for synchronizing smart antennaapparatus 16 with base station transceiver 24. At step 214, the signalsare communicated from splitter 50 to first filter 52 via path 70. Thesignals are filtered by first filter 52 at step 216. In one embodiment,first filter 52 includes attenuator 72 and band pass filter 74. In thisembodiment, the amplitude of the signals is reduced by attenuator 72,and frequencies outside the band of frequencies defined by the downlinkcontrol frequency are blocked or absorbed by band pass filter 74.

At step 218, the signals are communicated to signal mixer 54 and mixed,or combined, with a conversion signal 76 in order to convert the signalsfrom one frequency to another frequency. For example, the signals may beconverted from the transmission (or downlink) frequency at which thesignals were transmitted from base station transceiver 24 to acorresponding receiving (or uplink) frequency at which the signals maybe received by receiver 58. For example, in a P/E/R-GSM 900 or a GSM 850environment in which corresponding uplink and downlink frequencies areoffset by 45 MHz, conversion signal 76 may be approximately a 45 MHzsignal.

The signals output by mixer 54 are filtered by second filter 56 at step220. In one embodiment, second filter 56 includes bandpass filter 78 andattenuator 80. In this embodiment, frequencies outside the band offrequencies defined by the receiving frequency are blocked or absorbedby band pass filter 78, and the amplitude of the resulting signals isreduced by attenuator 80.

At step 222, the radio signals, which have been converted to thereceiving frequency and filtered, are received by receiver 58. Thereceived signals are converted from analog to digital signals by sampler60 at step 224. The digital signals are then received by processor 62,which applies one or more synchronization algorithms 82 to the signalsto synchronize smart antenna apparatus 16 with base station transceiver24 in time and frequency.

Synchronization algorithms 82 are discussed in greater detail below withreference to FIGS. 7 and 8. Synchronization algorithms 82 may be appliedto radio signals received from base station transceiver 24 duringpower-up of smart antenna apparatus 16 to achieve accuratesynchronization, such as discussed below with reference to FIG. 7. Inaddition, one or more of the synchronization algorithms 82 may beapplied to radio signals received from base station transceiver 24during steady state operation of smart antenna apparatus 16 to maintainthe accurate synchronization, such as discussed below with reference toFIG. 8.

FIG. 7 illustrates a method of synchronizing smart antenna apparatus 16with base station transceiver 24 in time and frequency during power-upof smart antenna apparatus 16. The following discussion concerns one ormore embodiments in a GSM environment. It should be understood that inother embodiments, similar methods may be used for other standards, forexample CDMA (Code Division Multiple Access) standards such as IS-95Aand IS-95B, CDMA 2000, WCDMA, TD SCDMA, TETRA, and TDMA (Time DivisionMultiple Access) standards such as IS-136 and IS-54, without departingfrom the scope of the present invention.

At step 248, processor 62 determines the control frequency being used bybase station system 12. In some embodiments, processor 62 uses a controlfrequency detector 94 to determine the control frequency. Controlfrequency detector 94 may be operable to determine the control frequencyby determining the average energy being transmitted at each frequencyband within an appropriate bandwidth. For example, in a GSM environment,control frequency detector 94 may determine the average energy beingtransmitted at each 200 kHz frequency band within the 25 MHz bandwidthof the GSM standard. The frequency band having the highest averageenergy level is determined to be the control frequency.

At step 250, processor 62 may execute coarse timing synchronizationalgorithm 86 to roughly synchronize smart antenna apparatus 16 with basestation transceiver 24 in time. Coarse timing synchronization algorithm86 may be operable to locate the control channel within a multi-frame.In addition, coarse timing synchronization algorithm 86 may be operableto synchronize smart antenna apparatus 16 with base station transceiver24 with sufficient accuracy such that the location of a particular timeslot within a particular frame of the multi-frame may be determined byframe synchronization algorithm 88, as described below in step 254.

Coarse timing synchronization algorithm 86 samples a series of time slotintervals for a period equal to a GSM multi-frame. The beginning of thefirst time slot interval in the series is determined randomly. Ingeneral, coarse timing synchronization algorithm 86 attempts to locate afrequency correction burst (FCCH), which is transmitted in the controlslot in every tenth frame. To locate a frequency correction burst, acorrelation is performed between the signal received at each time slotinterval and the known frequency correction burst. The correlationbetween the received signals and the expected frequency correction burstFCCH(n) can be determined using the following equation:

$\begin{matrix}{{{FCCH\_ CORR}\left\lbrack {i,j} \right\rbrack} = {\sum\limits_{n = 0}^{N}\;{Y_{i,j}\;(n)*{FCCH}^{H}\;\left( {N - n} \right)}}} & (1)\end{matrix}$where:

-   -   i indicates the slot number in a GSM multi-frame (i=(0–51        frames)*8 time slots per frame);    -   j indicates the slot sync pulse offset from the first random        selection (j=0 . . . (N/offset_delta));    -   Y(n) is the signal received by processor 62 from sampler 60;    -   FCCH(n) as the expected frequency correction burst as defined in        GSM standard 05.02; and    -   FCCH_CORR[i,j] is the correlation between the received signals        Y(n) and the expected frequency burst FCCH(n).

The offset ĵ that will yield maximum correlation can be written as:

$\begin{matrix}{\hat{j} = {\arg\mspace{14mu}{\max_{j}\;\left( {\sum\limits_{k = 0}^{MULTI\_ FRAME}\;{{FCCH\_ CORR}\left\lbrack {k,j} \right\rbrack}} \right)}}} & (2)\end{matrix}$

After determining the offset ĵ using Equation (2), the beginning of theseries of time slot intervals should be changed to the location of ĵthat yields the maximum correlation.

At step 252, it may be determined whether the offset in time betweensmart antenna apparatus 16 and base station system 12 is greater than aspecific offset. If so, step 250 may be repeated until the offset isless than or equal to the specific offset. If the offset is less than orequal to the specific offset, the method continues to step 254.

At step 254, processor 62 executes frame synchronization algorithm 88 tolocate a particular time slot in a particular frame of a multi-frame. Inparticular, synchronization algorithm 88 may be operable to determinethe location of the first time slot, or time slot 0, in a GSMmulti-frame. In one embodiment, frame synchronization algorithm 88 maynot be executed until coarse timing synchronization algorithm 86 hasbeen executed. Frame synchronization algorithm 88 samples a GSM timeslot from the point ĵ determined using coarse timing synchronizationalgorithm 86 in step 250 above. The sampled GSM slot is correlated witha frequency correction burst (FCCH) using the following equation:

$\begin{matrix}{{{FCCH\_ CORR}\lbrack i\rbrack} = {\sum\limits_{n = 0}^{N}\;{Y_{i}\;(n)*{FCCH}^{H}\;\left( {N - n} \right)}}} & (3)\end{matrix}$where:

-   -   i indicates the slot number in a GSM multi-frame (i=(0–51        frames)*8 time slots per frame);    -   Y(n) is the signal received by processor 62 and sampled for the        interval of a GSM time slot.    -   FCCH(n) is the expected frequency correction burst as defined in        GSM standard 05.02; and    -   FCCH_CORR[i] is the correlation between the received signal Y(n)        and the expected frequency correction burst FCCH(n).

The beginning of a GSM multi-frame (î), which may be referred to as slot0, may be determined as follows:i=arg max_(i)(FCCH _(—) CORR[i]+FCCH _(—) CORR[i+88])  (4)At step 256, processor 62 may execute fine timing correction algorithm90. Fine timing correction algorithm 90 is operable to sample the signalreceived from sampler 60 during the time slot in a multi-frame in whicha synchronization burst (SCH) is expected according to GSM standards,such as GSM standard 05.02. The correlation between the signal receivedfrom sampler 60 and the expected synchronization burst can be determinedas follows:∀i 0<i<correlation_window:

$\begin{matrix}{{{SCH\_ CORR}\lbrack i\rbrack} = {\sum\limits_{n = 0}^{N}\;{Y\;\left( {{n0} + i + n} \right)*{SCH\_ SEQ}^{H}\;\left( {N - n} \right)}}} & (6)\end{matrix}$where:

-   -   correlation_window indicates the length of the correlation        search, for example a particular number of frames;    -   Y(n) is the signal received by processor 62 and sampled for the        interval of a GSM time slot.    -   SCH_SEQ(n) is the expected synchronization burst according to        GSM standard 05.02; and    -   SCH_CORR[i] is the correlation between the received signal Y(n)        and the expected synchronization burst SCH(n).        The correct timing offset (î) may be determined as follows:        i=arg max_(i)(SCH _(—) CORR(i))  (7)        The fine time correction d may be determined as follows:

$\begin{matrix}{d = \frac{\left( {{{SCH\_ CORR}\left\lbrack {i - 1} \right\rbrack} - {{SCH\_ CORR}\left\lbrack {i + 1} \right\rbrack}} \right)*{\Delta/2}}{\left( {{{SCH\_ CORR}\left\lbrack {i - 1} \right\rbrack} + {{SCH\_ CORR}\left\lbrack {i + 1} \right\rbrack} - {2*{{SCH\_ CORR}\lbrack i\rbrack}}} \right)}} & (8)\end{matrix}$where Δ is the time between two samples. The fine time correction offsetmay then be calculated from the expected location of the synchronizationburst (SCH) as follows:Fine time correction=(î+d)−expected SCH  (9)

In some embodiments, fine timing synchronization algorithm 90synchronizes smart antenna apparatus 16 with base station transceiver 24with an accuracy of less than about 1 GSM bit, which is approximatelyequal to 3.7 microseconds. In other words, smart antenna apparatus 16 isoffset from base station system 12 by less than 1 GSM bit. In oneembodiment, fine timing synchronization algorithm 90 is operable tosynchronize smart antenna apparatus 16 with base station transceiver 24with an accuracy of less than one quarter of one GSM bit, which isapproximately equal to 0.9 microseconds.

At step 260, processor 62 may execute frequency synchronizationalgorithm 92 to synchronize smart antenna apparatus 16 with base stationtransceiver 24 in frequency. Frequency synchronization algorithm 92 isbased on a Fourier's analysis of a frequency correction burst (FCCH) inthe signal received from sampler 60. The Fast Fourier Transform,FFT_FCCH[k] of Y(n), may be determined as follows:

$\begin{matrix}{{{FFT\_ FCCH}\lbrack k\rbrack} = {\sum\limits_{n = 0}^{N - 1}\;{Y\;(n)*{EXP}\;\left( {- \frac{j*2*\Pi*k*n}{N}} \right)}}} & (10)\end{matrix}$where Y(n) is the frequency correction burst received by processor 62and sampled for the interval of a GSM time slot, and k is the frequencyindex. The frequency correction burst (FCCH) frequency.({circumflex over(f)}) may be determined as follows:{circumflex over (f)}=arg max_(FFT) _(—) _(SIZE/2<f<FFT) _(—)_(SIZE)(FFT _(—) FCCH[f])  (11)The fine frequency correction d may be determined as follows:

$\begin{matrix}{d = \frac{\left( {{{FFT\_ FCCH}\left\lbrack {k - 1} \right\rbrack} - {{FFT\_ FCCH}\left\lbrack {k + 1} \right\rbrack}} \right)*{\Delta/2}}{\left( {{{FFT\_ FCCH}\left\lbrack {k - 1} \right\rbrack} + {{FFT\_ FCCH}\left\lbrack {k + 1} \right\rbrack} - {2*{{FFT\_ FCCH}\lbrack k\rbrack}}} \right)}} & (12)\end{matrix}$where Δ is the frequency resolution of the fast Fourier transform (FFT).The frequency offset (ΔF) may then be determined as follows:

$\begin{matrix}{{\Delta\; F} = \frac{1625\text{/}24\mspace{14mu}{KHz}}{\left( {\left( {\hat{f} + d} \right) - {{fft\_ size}/2}} \right)}} & (13)\end{matrix}$The frequency of smart antenna apparatus 16 may then be corrected by thefrequency offset (ΔF). In one embodiment, frequency synchronizationalgorithm 92 is operable to synchronize smart antenna apparatus 16 withbase station transceiver 24 within an accuracy of about 50 Hz.

At step 262, it may be determined whether the frequency offset in timebetween smart antenna apparatus 16 and base station system 12 is greaterthan a defined frequency offset. If so, step 260 may be repeated untilthe offset is less than or equal to the defined frequency offset. If theoffset is less than or equal to the defined frequency offset, the timingsynchronization may be re-checked at step 264. The timingsynchronization may be re-checked at step 264 because the timesynchronization and the frequency synchronization may be related suchthat smart antenna system 16 must be synchronized in time in order to besynchronized in frequency, and vice versa. The accuracy of the timesynchronization achieved at 256 may be affected by the frequencysynchronization performed in 260. Thus, the time synchronization isre-checked as step 264 to ensure that the time offset between smartantenna apparatus 16 and base station system 12 is still less than orequal to the second defined offset. If so, smart antenna apparatus 16may enter steady state operation at step 266. If not, steps 256 through264 are repeated until smart antenna apparatus 16 is synchronized inboth time and frequency.

The time and frequency synchronization between smart antenna apparatus16 and base station system 12 achieved using the methods of FIG. 4 maybe maintained during steady state operation as described below withreference to FIG. 5.

FIG. 8 illustrates a method of maintaining smart antenna apparatus 16and base station transceiver 24 synchronized in time during steady stateoperation of the smart antenna apparatus. At step 300, smart antennaapparatus 16 operates in steady state. For example, smart antennaapparatus 16 may operate in steady state after being synchronized intime and frequency during power-up, as discussed above with reference toFIG. 7.

At step 302, smart antenna apparatus 16 may check the timesynchronization of smart antenna apparatus 16 periodically, randomly, orin response to some event. It is determined whether the time offsetbetween smart antenna apparatus 16 and base station system 12 is greaterthan a defined steady-state time offset. The defined steady-state timeoffset may be the same as, or different than, the second defined offsetused in synchronizing during power-up, as discussed above with referenceto step 258 in FIG. 7.

If the time offset determined at step 302 is less than or equal to thedefined steady-state time offset, no time synchronization correction isneeded and smart antenna system remains in steady-state operation.However, if the time offset determined at step 302 is greater than thedefined steady-state time offset, the time and/or frequencysynchronization may be corrected at steps 304 through 314.

In the embodiment shown in FIG. 8, steps 304 through 312 are essentiallythe same as steps 256 through 264 of FIG. 7. Processor 62 executes finetiming synchronization algorithm 90 to adjust or correct the timesynchronization at step 304. The time synchronization is then re-checkedat step 306, and if necessary, re-synchronized at step 304, until thetime offset is less than or equal to the defined steady-state timeoffset. Fine frequency synchronization algorithm 92 is executed at step308, and the frequency offset between smart antenna apparatus 16 andbase station system 12 is checked against a defined steady-statefrequency offset at step 310. The defined steady-state frequency offsetmay be the same as, or different than, the defined frequency offset usedin synchronizing during power-up, as discussed above with reference tostep 262 in FIG. 7.

Since the frequency synchronization performed at step 308 may affect thetime synchronization of smart antenna apparatus 16, the timesynchronization is re-checked at step 312 to ensure that the time offsetbetween smart antenna apparatus 16 and base station system 12 is stillless than or equal to the defined steady-state time offset. If so, smartantenna apparatus 16 may return to steady state operation. If not, steps304 through 310 are repeated until smart antenna apparatus 16 issynchronized in both time and frequency.

According to the method shown in FIG. 8, smart antenna apparatus 16 maybe maintained in accurate time and frequency synchronization duringsteady-state operation of smart antenna apparatus 16. In someembodiments, only fine tuning, such as using fine timing synchronizationalgorithm 90 and fine frequency synchronization algorithm 92, isrequired during steady state operation. Thus, in some embodiments, it isnot necessary to execute coarse timing synchronization algorithm 86 orframe synchronization algorithm 88 during steady state operation ofsmart antenna apparatus 16.

FIGS. 9 and 10 illustrate an example system and method for collectingsignaling information being communicated between base station controller26 and base station transceiver 24, extracting relevant information fromthe signaling information, and communicating the relevant information toprocessing system 102 to be used as an input in making beam selectiondecisions.

FIG. 9 illustrates an embodiment of a smart antenna system 16 operableto receive and process signaling information being communicated betweenbase station controller 26 and base station transceiver 24. In general,signaling information monitoring system 106 may be coupled to interface36 such that signaling information monitoring system 106 may receive, ormonitor signaling information being communicated between base stationcontroller 26 and base station transceiver 24 via interface 36. Thisinformation may then be filtered and/or otherwise processed to determinerelevant signaling information 180 which may be used by smart antennaapparatus 16 in performing smart antenna functions, such as making beamselection decisions.

As discussed above with reference to FIG. 1, base station controller 26and base station transceiver 24 may communicate traffic information andsignaling information with each other via interface 36. Interface 36 maysupport one or more communication channels. Interface 36 may support oneor more traffic channels for communicating voice or data signals and onemore signaling channels for communicating signaling, or control,information. The signaling, or control, information may compriseinformation regarding the one or more traffic channels. In a GSMenvironment, interface 36 may comprise an A-bis interface between a BaseStation Controller (BSC) and a Base Transceiver Station (BTS). Interface36 may comprise one or more E1/T1 cables. In a 3G environment, interface36 may comprise an LUB interface between a Radio Network Controller(RNC) and a Node B base station.

Smart antenna system 16 may comprise signaling information monitoringsystem 106, processing system 102, and storage system 103. Signalinginformation monitoring system 106 may comprise a monitoring unit 160 andan extracting unit 162. Monitoring unit 160 is generally operable tocollect, or monitor, information being communicated between base stationcontroller 26 and base station transceiver 24 via interface 36, andextracting unit 162 is generally operable to extract relevant signalinginformation 180 from the information collected by monitoring unit 160.

Monitoring unit 160 may comprise a signal splitter 164, a first decodingmodule 166, and a second decoding module 168. In one embodiment,monitoring unit 160 is an LAPD (Link Access Procedure on the D-Channel)monitoring unit. Signal splitter 164 is generally operable to couplesignaling information monitoring system 106 to interface 36. Inparticular, signal splitter 164 is operable to split interface 36 toprovide a first path 169 connecting base station controller 26 and basestation transceiver 24 and a second path 170 for signaling information182 to be processed by signaling information monitoring system 106.Signal splitter 164 may comprise a T-connection that creates first path169 and second path 170.

Signal splitter 164 may be operable to split interface 36 to providepath 170 for signaling information 182 without affecting thecommunication of signaling information 182 or traffic informationbetween base station controller 26 and base station transceiver 24 viainterface 36. In one embodiment, signal splitter 164 connects signalinginformation monitoring module 106 with interface 36 using high impedancesuch that signal splitter 164 does not interfere with interface 36, evenif smart antenna apparatus 16 is turned off or not operational. In otherwords, the monitoring of signaling information 182 being communicatedbetween base station controller 26 and base station transceiver 24 maybe entirely passive. For example, the monitoring of signalinginformation 182 may be done without using active components. In oneembodiment, the monitoring of signaling information 182 is done withoutamplifying the signal being communicated via interface 36.

Thus, smart antenna apparatus 16 may be operable to monitor signalinginformation 182 being communicated between base station transceiver 24and base station controller 26 without affecting, or disturbing, thecommunication of the signaling information 182 between base stationtransceiver 24 and base station controller 26. In some embodiments,smart antenna apparatus 16 is operable to monitor signaling information182 without introducing any delay in the communication of signalinginformation 182 between base station transceiver 24 and base stationcontroller 26.

In addition, smart antenna apparatus 16 may be non-obtrusively coupledto interface 36. Thus, in some embodiments, the components of basestation system 12, including base station transceiver 24 and basestation controller 26, do not need to be modified, altered, orreconfigured in order for smart antenna apparatus 16 to monitorsignaling information 182 being communicated between base stationcontroller 26 and base station transceiver 24. Thus, the cost and laborof modifying or altering base station system 12 and/or dealing ornegotiating with the manufacturer of the components of base stationsystem 12, such as base station transceiver 24 and base stationcontroller 26, is reduced or, in some embodiments, eliminated.

First decoding module 166 is operable to receive signals from interface36 via path 170. First decoding module 166 is generally operable toperform a first level of decoding of signals received from interface 36.In some embodiments, first decoding module 166 is an E1/T1 decodingmodule. Second decoding module 168 is operable to further decode datareceived from first decoding module 166. In some embodiments, seconddecoding module 168 is a Layer 2 (LAPD) (Link Access Procedure on theD-Channel) decoder.

Extracting unit 162 may comprise a first filtering module 172, a thirddecoding module 174, a second filtering module 176, and a pre-processingmodule 178. In one embodiment, extracting unit 162 is an LAPD processingunit. Extracting unit 162 is generally operable to extract relevantinformation from data received from monitoring unit 160. In oneembodiment, extracting unit 162 is operable to extract relevantinformation available only at A-bis levels higher than the E1/T1physical level.

First filtering module 172 is operable to filter data received fromsecond decoding module 168. In some embodiments, first filtering module172 is an LAPD filtering module. Third decoding module 174 is operableto decode data received from first filtering module 172. In someembodiments, third decoding module 174 is a Layer 3 BTSM (BaseTransceiver Station Management) decoding module. Second filtering module176 is operable to filter or decode data received from third decodingmodule 174. In some embodiments, second filtering module 176 is an IE(Information Elements) filtering module.

Preprocessing module 178 is operable to organize the data received fromsecond filtering module 176 such that the data may be used by one ormore modules or systems of smart antenna apparatus 16 for performing theoperations of smart antenna apparatus 16. For example, preprocessingmodule 178 may be operable to organize the data such that the processingsystem 102 may use the data in making beam selection determinations. Inone embodiment, preprocessing module 178 may be operable to organize thedata into categories of transactions which may be relevant to one ormore modules or systems of smart antenna apparatus 16. For example, thecategories of transactions may include registration, mobile originatedcalls (MOC), mobile terminated calls (MTC), location update, andhandover.

The information or data output from signaling information monitoringsystem 106 may be generally referred to as relevant signalinginformation 180. It should be understood that the term relevantsignaling information 180 as used throughout this document may refer toall or any portion of the information output from signaling informationmonitoring system 106.

Relevant signaling information 180 may be used for various functionswithin smart antenna system 14, and may include such information asfrequency hopping information, mobile originated call (MOC) information,mobile terminated calls (MTC) information, mobile frequency information,mobile timing information, mobile sequence information, and handoverinformation. For example, relevant signaling information 180 may be usedby processing system 102 in making beam selection determinations.Relevant signaling information 180 may be used to simplify or reduce theprocessing time required for determining a correlation qualitycorresponding to each narrow beam 34 for use in making beam selectiondecisions (for example, see the discussion below regarding FIGS. 19 and21). In addition, relevant signaling information 180 may be used toverify beam selections determined by one or more beam selection modules.In some embodiments, relevant signaling information 180 includesinformation relevant to frequency hopping, which may be used to verifybeam selections determined by one or more beam selection modules and/orselect an appropriate beam according to the frequency hoppinginformation (for example, see discussion below regarding FIGS. 17 and18). As another example, relevant signaling information 180 may be usedto synchronize or check the synchronization of smart antenna apparatus16 with base station transceiver 24.

In some embodiments, signaling information 182 being communicatedbetween base station controller 26 and base station transceiver 24 isnot encrypted which allows signal information monitoring system 106 todecode signaling information 182. Thus, smart antenna system 14 isoperable to collect relevant information regarding traffic channels in apractical and relatively inexpensive manner. Smart antenna system 14provides an advantage over other smart antenna systems which collectinformation regarding traffic channels from a higher level interface,such as the A-Interface, since such systems often require long andexpensive cabling. In addition, smart antenna system 14 provides anadvantage over other smart antenna systems which collect informationregarding traffic channels from an air interface, such as the M-AirInterface, since such systems often provide inaccurate results and aremore expensive, particularly in certain environments, such as frequencyhopping or GPRS (Global Packet Radio Service) environments, for example.

FIG. 10 illustrates a method of collecting relevant signalinginformation in accordance with an embodiment of the present invention.At step 330, the method starts. At step 332, signaling information 182being communicated between base station controller 26 and base stationtransceiver 24 via interface 36 is received by signaling informationmonitoring system 106. Signaling information 182 may be received bysplitter 164. In a GSM environment, interface 36 is an A-bis interface.In a 3G environment, interface 36 is a LUB interface. At step 334,splitter 164 splits the path of signaling information 182 into a firstpath between base station controller 26 and base station transceiver 24and a second path 170 for use by signaling information monitoring system106.

At step 336, first decoding module decodes the signaling information 182received via path 170. At step 338, second decoding module 168 furtherdecodes data received from first decoding module 166. At step 340, firstfiltering module 172 filters the data received from second decodingmodule 168. At step 342, third decoding module 174 further decodes datareceived from first filtering module 172. At step 344, second filteringmodule further filters or decodes data received from third decodingmodule 174. At step 346, preprocessing module 178 organizes the datareceived from second filtering module 176 such that the data may be usedby one or more modules or systems of smart antenna apparatus 16. At step348, the method stops.

FIGS. 11 through 23 illustrate example embodiments of systems andmethods for selecting beams in a smart antenna system. FIG. 11illustrates a system for determining receiving beam selections 126 andtransmitting beam selections 124 in one frequency in an embodiment ofthe present invention. As discussed above with reference to FIG. 3,receiving unit 108 may comprise a beam receiver 112 corresponding witheach uplink beam 130 associated with smart antenna system 14. Forexample, in one embodiment, receiving unit 108 comprises seven beamreceivers 112, each corresponding with one of seven uplink beams 150associated with smart antenna system 14. And as discussed above withreference to FIG. 9, signaling information monitoring system 106 isoperable to obtain relevant signaling information by monitoring thesignaling information being communicated between base stationtransceiver 24 and base station controller 26.

As discussed above with reference to FIG. 4, processing system 102comprises a processing module 62 for each frequency used by base stationtransceiver 24 as well as a central processing unit 188. Each processingmodule 62 comprises one or more beam analysis modules 398, one or morebeam selection modules 404, and a storage module 406. Beam analysismodules 398 are generally operable to analyze received signals todetermine one or more characteristics or parameters, which are used bybeam selection modules 404 in determining receiving beam selections 126and/or transmitting beam selections 124.

In the embodiment shown in FIG. 11, beam analysis modules 398 comprise acorrelation module 400, a signal strength module 402, and a relevantpower module 403. Correlation module 400 is generally operable tocorrelate received signals with known signals to determine the qualityof the received signals. In one embodiment, correlation module 400 isoperable to correlate signal sequences received via one or more beamswith one or more known training sequences in order to determine acorrelation quality of each of the beams. These correlation qualitiesmay be used as input in beam selection module 404 for use in selectingreceiving beam selections 126 and/or transmitting beam selections 124.Correlation module 400 is described below in greater detail withreference to FIG. 19.

Signal strength module 402 is generally operable to determine the signalstrength, or power, of received signals. In some embodiments, signalstrength module 402 is operable to determine the signal strength of theuplink beam 130 received from each beam receiver 112 in frequencyreceiving unit 108. For example, signal strength module 402 maydetermine a received signal strength indicator (RSSI) for each uplinkbeam 130. In one embodiment, signal strength module 402 is operable todetermine an average signal strength for each uplink beam 130 over aperiod of time. Like the correlation qualities determined by correlationmodule 400, the signal strengths determined by signal strength module402 may be used as an input in beam selection module 404 for use inselecting receiving beam selections 126 and/or transmitting beamselections 124.

Relevant power module 403 is generally operable to determine thestrength, or power, of received signals relative to some baseline. Forexample, relevant power module 403 may receive uplink beams 150 fromreceiving unit 108 and measure the relevant power 439 of each uplinkbeam 130. The relevant power 439 of each uplink beam 130 may be based onthe input power of that uplink beam 130 received at the correspondingbeam receiver 112 and the current gain of that beam receiver 112, asdescribed in greater detail below with reference to FIGS. 12 and 13.

Beam selection modules 404 are generally operable to select one or moreappropriate beams for transmitting signals to or receiving signals frommobile stations 15 based on one or more inputs or parameters, such asinformation received from beam analysis modules 398, signalinginformation monitoring system 106, and storage module 406, for example.Beam selection modules 404 may be operable to determine receiving beamselections 126 and/or transmitting beam selections 124. In someembodiments, beam selection modules 404 include a fast decision beamselection module 408 and a smart decision beam selection module 410. Ingeneral, fast decision beam selection module 408 is operable to makerelatively fast beam selection decisions substantially in real time.Smart decision beam selection module 410 is generally operable to makebeam selection decisions based on further analysis of inputs andparameters. Beam selection modules 404 may also include a selected beamdecision module, such as a fast/smart decision beam selection module 416to determine whether to use the results of fast decision beam selectionmodule 408 or smart decision beam selection module 410 in particularcircumstances.

Storage module 406 is generally operable to store information receivedfrom beam analysis modules 398, beam selection modules 404, signalinginformation monitoring system 106, and/or any other component of smartantenna system 14. In some embodiments, storage module 406 is operableto store information from beam analysis modules 398 to be used by smartdecision beam selection module 410.

In operation, uplink beams 150 received by receiving unit 108 arecommunicated to the corresponding processing module 62. Beam analysismodules 398 analyzes uplink beams 150 to determine one or morecharacteristics or parameters of each uplink beam 130. In someembodiments, correlation module 400 determines a correlation quality foreach uplink beam 130 based on a correlation between the signal sequencescommunicated in each uplink beam 130 with one or more known trainingsequences. In one embodiment, correlation module 400 correlates eachuplink beam 130 with each known training sequence to determine thecorrelation quality for that uplink beam 130. In another embodiment,correlation module 400 determines the correlation quality for eachuplink beam 130 by correlating that uplink beam 130 with an appropriateone of the known training sequences, which is determined based onrelevant signaling information 180 received from signaling informationmonitoring system 106. In addition, signal strength module 402 maydetermine a signal strength for each uplink beam 130.

Beam selection modules 404 may then determine receiving beam selections126 and/or transmitting beam selections 124 based on one or more inputs.In one embodiment, these inputs include the current correlation qualityand signal strength determined for each uplink beam 130 as well aspreviously determined correlation qualities and signal strengths storedin storage module 406. Fast decision beam selection module 408 and smartdecision beam selection module 410 may determine a fast decision beamselection and a smart decision beam selection, respectively. The fastdecision beam selection and the smart decision beam selection may be thesame or different beams, depending on the circumstances. Fast/smartdecision beam selection module 416 may determine whether to use the fastdecision beam selection, the smart decision beam selection, or neitherdepending on the circumstances.

It should be understood that the embodiment shown in FIG. 11 focuses onthe system and methods for selecting receiving beam selections 126 andtransmitting beam selections 124 for one of the frequencies used by basestation transceiver 24. Smart antenna system 14 may use similar oridentical systems or methods to select receiving beam selections 126 andtransmitting beam selections 124 for each of the other frequencies usedby base station transceiver 24. It should also be understood that insome embodiments, more than one uplink beam 130 may be selected by beamselection modules 404 for receiving and/or transmitting signals. Forexample, in one embodiment, beam selection modules 404 are operable toselect the two best uplink beams 150 to be communicated to base stationtransceiver 24. In addition, in some embodiments in which smart antennasystem is an adaptive antenna system, beam selection modules 404 may beoperable to select one or more uplink beams 150 and/or one or moredownlink beams 132 such that beam forming network 128 may form anappropriately-shaped beam for receiving signals from and transmittingsignals to mobile stations 15.

FIGS. 12 through 15 illustrate a fast decision beam selection system andmethod in accordance with an embodiment of the present invention. Inparticular, FIG. 12 illustrates a system for determining fast beamselections 440 including a receiving unit 108 for a particularfrequency, relevant power module 403, fast decision beam selectionmodule 408, host processor 118, and receiving beam switch 127. Asdiscussed above with reference to FIGS. 2 and 3, frequency receivingunit 108 associated with a particular frequency is operable to receiveuplink beams 150 from antenna unit 18. Frequency receiving unit 108 mayinclude a beam receiver 112 operable to receive each uplink beam 130.Uplink beams 150 received by frequency receiving unit 108 may becommunicated along a first path to receiving beam switch 127 and along asecond path to an appropriate processing module 62. Receiving beamswitch 127 may allow one or more uplink beams 150 to pass through tobase station transceiver 24 based on the current selected receiving beamselection 126. Processing module 62 is operable to determine a fastdecision beam selection 440 that may be used as the current receivingbeam selection 126, depending on the situation.

Frequency receiving unit 108 may include an AGC (Automatic Gain Control)device 482 operable to control the gain of each beam receiver 112. Inoperation, AGC device 482 may control the gain of each beam receiver 112based on the strength of input signals received via each uplink beam 130such that the output strength of each beam receiver 112 is the same orsimilar. However, AGC device 482 may be locked such that the gain ofeach beam receiver 112 is held constant, and thus the strength of theoutput of each beam receiver 112 may vary depending on the strength ofthe input signals being received via each uplink beam 130. AGC device482 may be locked such that the gain of each beam receiver 112 is heldat a constant value equal to a gain setting 490 determined by centralprocessing unit 118. In one embodiment, AGC device 482 is turned off atthe beginning of a fast decision time slot such that the signal strengthof each uplink beam 130 may be measured and compared against each otherand/or against a threshold value, as discussed below in greater detail.

Central processing unit 118 may comprise a gain control module 488generally operable to determine gain settings 490 for each beam receiver112 based on one or more inputs. Gain control module 488 may comprise again storage unit 494 generally operable to store gain values for eachbeam receiver 112. Gain storage unit 494 is operable to receive andstore gains values determined by AGC device 482 during operation of AGCdevice 482. Gain control module 488 is operable to determine a gainsetting 490 for each beam receiver 112, as described in greater detailbelow with reference to FIGS. 14 and 15. The gain settings 490 for eachbeam receiver 112 are communicated to receiving system 100 and used toset the gain of each beam receiver 112 for the beginning of a particulartime slot in which AGC device 482 is turned off.

As shown in the embodiment of FIG. 12, processing module 62 comprisesfast decision beam selection module 408 and signal strength module 402.Fast decision beam selection module 408 comprises a filter, or buffer,480 and one or more fast decision algorithms 430. Buffer 480 and fastdecision algorithms 430 are generally operable to determine fastdecision beam selections 440 based at least in part on inputs receivedfrom signal strength module 402. Buffer 480 may include an average powercalculator 436 operable to determine average signal strengths based on aplurality of samples within buffer 480. Fast decision algorithms 430 mayinclude a minimum threshold 432 and an improvement threshold 434,discussed in greater detail below.

As discussed above with reference to FIG. 11, relevant power module 403may be operable to receive uplink beams 150 from receiving system 100and measure the relevant power 439 of each uplink beam 130. The relevantpower 439 of each uplink beam 130 may be based on the input power ofthat uplink beam 130 received at the corresponding beam receiver 112 andthe current gain of that beam receiver 112. For example, if the inputpower of an uplink beam 130 received at a beam receiver 112 is 5 dB andthe current gain of that beam receiver 112 is −2 dB, the relevant power439 of that uplink beam 130 is 3 dB.

Relevant power module 403 may be operable to repetitively sample therelevant power 439 of each uplink beam 130. In a particular embodiment,relevant power module 403 is operable to sample the relevant power 439for each uplink beam 130 at the approximate rate of seven times per GSMbit. In another embodiment, relevant power module 403 is operable tosample the relevant power 439 for each uplink beam 130 approximately 24times every GSM bit.

Fast decision beam selection module 408 is operable to receive thesampled relevant power 439 of each uplink beam 130 from relevant powermodule 403. Buffer 480 is operable to receive each sample of therelevant power 439 of each uplink beam 130. Buffer 480 includes anaverage power calculator 436 operable to determine an average power 484of each uplink beam 130 over a particular period of time or based on aparticular number of samples of the relevant power 439 that uplink beam130 within buffer 480. For example, in one embodiment, average powercalculator 436 may be operable to determine the average power 484 ofeach uplink beam 130 based on the six most recent samples received fromrelevant power module 403. In addition, average power calculator 436 maybe operable to update the average power 484 of each uplink beam 130after each new sample or after some number of new samples received fromrelevant power module 403. Thus, the average power 484 of each uplinkbeam 130 may be dynamic. In a particular embodiment, average powercalculator 436 calculates or updates the average power 484 of eachuplink beam 130 after every new sampling of relevant power 439 byrelevant power module 403.

Fast decision algorithm 430 is operable to determine the strongestuplink beam 130 (in other words, the uplink beam 130 with the highestaverage power 484) and to determine whether the average power 484 of thestrongest uplink beam 130 is greater than minimum threshold 432. Minimumthreshold 432 may be any appropriate value expressed in decibels orvolts. For example, in one embodiment, minimum threshold 432 isapproximately 9 dB. In another embodiment, minimum threshold 432 isapproximately 4 dB.

In one embodiment, if the average power 484 of the strongest uplink beam130 is greater than minimum threshold 432, fast decision beam selectionmodule 408 may select that uplink beam 130 as the fast decision beamselection 440. In that embodiment, if the average power 484 of thestrongest uplink beam 130 is less than minimum threshold 432, fastdecision beam selection module 408 may select none of the uplink beams150 as the fast decision beam selection 440. In another embodiment, ifthe average power 484 of the strongest uplink beam 130 is less thanminimum threshold 432, fast decision beam selection module 408 maintainsthe most recently selected fast decision beam selection 440.

Fast decision algorithm 430 may continue to analyze the dynamic averagepower 484 of each uplink beam 130 even after an uplink beam 130 has beenselected as fast decision beam selection 440. This may be done toidentify one or more other uplink beams 150 that may become strongerthan the current fast decision beam selection 440 as average powercalculator 436 continues to sample signal strengths 438 from signalstrength module 402. For example, suppose a relatively weak burst from afirst mobile station 15 is identified in a first uplink beam and thatbeam is selected as fast decision beam selection 440 in the beginning ofa time slot. Fast decision algorithm 430 may continue to search for astronger burst from a second 15 mobile station 15 arriving at smartantenna apparatus 16 via a second uplink beam later in the time slot. Ifthe burst identified in the second beam station is sufficiently strongerthan the burst identified in the first beam, fast decision beamselection module 408 may switch fast decision beam selection 440 fromthe first beam to the second beam.

As buffer 480 continues to update the average power 484 of each uplinkbeam 130, fast decision algorithm 430 may determine whether the averagepower 484 of the current strongest uplink beam 130 exceeds that of thecurrent fast decision beam selection 440 by an amount greater thanimprovement threshold 434. If fast decision algorithm 430 determinesthat current strongest uplink beam 130 does exceed that of the currentfast decision beam selection 440 by an amount greater than improvementthreshold 434, fast decision beam selection module 408 may switch fastdecision beam selection 440 to the current strongest uplink beam 130. Iffast decision algorithm 430 determines that current strongest uplinkbeam 130 does not exceed that of the current fast decision beamselection 440 by an amount greater than improvement threshold 434, fastdecision beam selection module 408 may maintain the most recentlyselected fast decision beam selection 440.

Fast decision algorithm 430 may continue to determine whether theaverage power 484 of the current strongest uplink beam 130 exceeds thatof the currently current fast decision beam selection 440 by an amountgreater than the improvement threshold 434, and fast decision beamselection module 408 may continue to switch the selected fast decisionbeam selection 440 accordingly. In some embodiments, fast decision beamselection module 408 continues switching or updating fast decision beamselection 440 as described above until a certain time is reached. Forexample, in a GSM environment, fast decision beam selection module 408may continue switching fast decision beam selection 440 until the lastpoint in the time slot in which a random access channel (RACH) signalcould be received by smart antenna apparatus 16. In particular, fastdecision beam selection module 408 continues switching fast decisionbeam selection 440 until the approximate middle of the time slot isreached. In one embodiment, fast decision beam selection module 408continues switching until the 61st GSM bit in the time slot is reached.

In another embodiment, fast decision beam selection module 408 continuesswitching or updating fast decision beam selection 440 as describedabove until the same uplink beam 130 remains the selected uplink beam130 for a defined time period. When the same uplink beam 130 remainsselected as fast decision beam selection 440 for a defined time period,that uplink beam 130 may be locked in and fast decision beam selectionmodule 408 may refuse to switch to any other uplink beam 130, regardlessof whether the average power 484 of the current strongest uplink beam130 exceeds the locked-in uplink beam 130 by the improvement threshold434. For example, in one embodiment, fast decision beam selection module408 continues switching fast decision beam selection 440 until the sameuplink beam 130 is selected as fast decision beam selection 440 for aperiod of time equal to approximately three GSM bits. In thisembodiment, when the same uplink beam 130 remains the fast decision beamselection 440 for approximately three GSM bits, that uplink beam 130 islocked in and fast decision beam selection module 408 will not switch toany other uplink beam 130.

Fast decision beam selection module 408 may be operable to determine, orswitch, fast decision beam selection 440 substantially in real time. Forexample, average power calculator 436 may determine the average power484 of each uplink beam 130 during based on signals received via eachuplink beam 130 in a first portion of a first time slot of a firstframe. Fast decision algorithm 430 may then select the uplink beam 130based at least in part on the average power 484 of each uplink beam 130.Receiving beam switch 127 may then switch to the selected uplink beam130 such that signals received via the selected uplink beam 130 in asecond portion of the first time slot of the first frame may becommunicated to the base station transceiver in real time.

In some embodiments, fast decision beam selection module 408 is operableto determine, or switch, fast decision beam selection 440 to theappropriate uplink beam 130 each time average power calculator 436calculates or updates the average power 484 of each uplink beam 130. Toprovide further illustration, suppose mobile station 15 communicates aRACH burst, such as a call initiation request or an access request,which is received by processing system 102 via a particular uplink beam130. Fast decision beam selection module 408 may identify the RACH burstand select the uplink beam 130 as fast decision beam selection 440before the end of the pre-message, tail, or guard portion of the burst.In one embodiment in a GSM environment, beam selection module 408 isoperable to select fast decision beam selection 440 during the 3 GSM bittail portion at the beginning of a burst.

Fast decision beam selection module 408 may be used in variety ofcircumstances. For example, beam selection decisions made by fastdecision beam selection module 408 may be used during the initiation ofa call by a mobile station 15 or in some situations in which thelocation of a mobile station 15 is unknown by smart antenna system 14.In particular, fast decision beam selection module 408 may be used tomake beam selection determinations regarding a communication initiationsignal, such as a random access channel (RACH) signal, received from amobile station 15, as described above. In addition, in some embodiments,beam selection determinations made by fast decision beam selectionmodule 408 are used initially after mobile station 15 has switched to aparticular traffic channel according to base station control signals.

Fast decision beam selection module 408 provides the ability to switchbeams in real time for communications about which smart antennaapparatus 16 has little or no previous information. In particular, fastdecision beam selection module 408 may be operable to select and switchbeams for call initiation signals received from mobile stations 15.Thus, since beam selection generally decreases interference andincreases the coverage or range of an antenna system, smart antennasystem 14 has a increased range for identifying initial signals, such asaccess requests or call initiation signals, from mobile stations 15 ascompared with traditional sector antennas or antennas that use beamselection techniques only after a call has been established.

FIG. 13 illustrates a method of fast decision beam selection inaccordance with an embodiment of the present invention. The methodstarts at step 700. In one embodiment, the method starts before aparticular time slot. In a particular embodiment, the method startsbefore a random access channel (RACH) time slot. At step 702, processingmodule 62 determines that fast decision beam selection module 408 willbe used to determine receiving beam selections 126 during the particulartime slot. At step 704, central processing unit 118 determines a gainsetting 490 for each beam receiver 112 based on one or more inputparameters, as discussed in greater detail below with reference to FIGS.14 and 15. At step 706, gain settings 490 and an AGC lock command 496are communicated to receiver unit 108 from central processing unit 118and processing module 62, respectively. At step 708, the gain of eachbeam receiver 112 is set according to gain settings 490 received fromprocessing module 62 and AGC device 482 is turned off, locking the gainof each beam receiver 112.

At step 710, the particular time slot begins. At step 712, uplink beams150 are received from antenna unit 18 by beam receivers 112. At step714, the relevant power 439 of each uplink beam 130 is determined byrelevant power module 403 and communicated to buffer 480. At step 716,buffer 480 calculates the average power 484 of each uplink beam 130based on a particular number of samples of the relevant power 439 ofeach uplink beam 130, including the sample determined at step 714 (inother words, the current sample). Step 716 may be repeated after everyone or more samples of relevant power 439 are determined at step 714.

At step 718, the strongest uplink beam 130 is determined by comparingthe average power 439 of each uplink beam 130. At step 720, it isdetermined whether the fast decision method has timed out. Inparticular, the fast decision method may time out after a particularpoint in the time slot is reached. In one embodiment in a GSMenvironment, the fast decision method times out after the 61st bit fromthe beginning of the time slot is reached. If it is determined at step720 that the fast decision method has timed out, the method proceeds tostep 722. At step 722, processing module 62 communicates an AGC unlockcommand 497 to receiving unit 108 which turns AGC device 482 back on. Atstep 724, AGC device 482 controls or adjusts, if necessary, the gain ofeach beam receiver 112 based on the input power of uplink beams 150received by each beam receiver 112. At step 726, the magnitude of thegain of each beam receiver 112 at the end of the time slot, as adjustedby AGC device 482, is communicated to central processing unit 118 foruse in determining gain settings 90 for subsequent time slots, asdiscussed below with reference to FIGS. 14 and 15. At step 727, themethod ends.

If it is determined at step 720 that the fast decision method has nottimed out, the method proceeds to step 728. At step 728, it isdetermined whether the average power 439 of the strongest uplink beam130 is greater than a defined signal power threshold, such as minimumthreshold 432. In one embodiment, this determination is made by fastdecision algorithm 430. If it is determined that the average power 439of the strongest uplink beam 130 is greater than minimum threshold 432,that uplink beam 130 is set as the fast decision beam selection 440 atstep 730. If not, the method returns to step 716 to continue calculatingand sampling the average power 439 of each uplink beam 130.

At step 732, fast decision algorithm 430 continues to update the averagepower 484 of each uplink beam 130 based on samples received fromrelevant power module 403. At step 736, the current strongest uplinkbeam 130 is determined based on the updated average power 484 of eachuplink beam 130. At step 738, it is determined whether the average power484 of the current strongest uplink beam 130 exceeds that of the uplinkbeam 130 currently selected as fast decision beam selection 440 by morethan the improvement threshold 434. In one embodiment, improvementthreshold 434 is the same as minimum threshold 432. In anotherembodiment, improvement threshold 434 is greater than minimum threshold432. In yet another embodiment, improvement threshold 434 is less thanminimum threshold 432. If it is determined at step 738 that the currentstrongest uplink beam 130 does exceed the currently selected fastdecision beam selection 440 by more than the improvement threshold 434,fast decision beam selection 440 is switched to the current strongestuplink beam 130 at step 740, and the method proceeds to step 744. Ifnot, the current fast decision beam selection 440 is maintained at step742.

At step 744, it is determined whether the fast decision method has timedout. Step 744 may be similar or identical to step 720. If it isdetermined at step 742 that fast decision method has timed out, steps722 through 727 may be performed. If it is determined at step 742 thatfast decision method has not timed out, the method may return to step732.

FIGS. 14 and 15 illustrate a system and method for determining gainsettings 490 for use in determining fast decision beam selections 440 inaccordance with an embodiment of the present invention. As shown in FIG.14, host processor 118 includes gain control module 488 that may includegain storage unit 494. Gain control module 488 is generally operable todetermine gain settings 490 for use in receiving unit 108 based on oneor more inputs. In one embodiment, these inputs include relevantsignaling information 754 received from signaling information monitoringmodule 106, AGC gain values 750 determined by AGC device 482, whether ornot fast decision beam selection module 408 selected a fast decisionbeam selection 440, and the current fast decision beam selection 440.Gain storage unit 494 is operable to receive and store AGC gain values750. Gain control module 488 may be operable to execute a gain controlalgorithm 752 to determine gain settings 490. Gain control algorithm 752is described in greater detail below with reference to FIG. 15.

Generally, gain control module 488 is operable to determine gainsettings 490 for each beam receiver 112 for the beginning of the nexttime slot (or for a particular time slot in the future) by selecting abaseline value for the gain of each beam receiver 112 and adjustingnone, one, several or all of the baseline values. In one embodiment, theAGC gain values 750 determined during the past time slot (in otherwords, during the portion of the past time slot in which AGC device 482was operating) are used as the baseline values for the gain of each beamreceiver 112. In another embodiment, the gain settings 490 determined bygain control module 488 for the beginning of the past time slot are usedas the baseline values for the gain of each beam receiver 112.

To determine gain settings 490, gain control module 488 may firstdetermine whether fast decision beam selection module 408 selected afast decision beam selection 440 (in other words, whether the strongestuplink beam 130 was greater than minimum threshold 432) during the pasttime slot. If fast decision beam selection module 408 did select a fastdecision beam selection 440 during the past time slot, gain controlmodule 488 may determine from relevant signaling information 754 whethera burst from a mobile station 15 was received in that time slot, orwhether the selected uplink beam 130 was receiving noise from some othersource. In one embodiment, if relevant signaling information 754indicates that there was a mobile station 15 communicating in that theslot, gain control module 488 sets gain settings 490 equal to thebaseline values for each beam receiver 112. On the other hand, ifrelevant signaling information 754 indicates that there was not a mobilestation 15 communicating in that time slot, then the selected uplinkbeam 130 was selected erroneously, and gain control module 488 may setgain settings 490 equal to the baseline values for each beam receiver112 except, but decrease the gain setting 490 for the beam receiver 112that received the selected uplink beam 130.

If fast decision beam selection module 408 does not select a fastdecision beam selection 440 for a particular period of time, such asover a span of a particular number of time slots, gain control module488 may increase the gain setting 490 of each beam receiver 112 by aparticular amount above the baseline values to increase the sensitivityof beam receivers 112.

FIG. 15 illustrates a method for determining gain settings 490 inaccordance with an embodiment of the present invention. In particular,FIG. 15 may illustrate gain control algorithm 752 operable to beexecuted by gain control module 488. At step 800, the method starts. Inone embodiment, the method may start after a particular time slot. Atstep 802, it is determined whether an uplink beam 130 was selected asfast decision beam selection 440 during the particular time slot. Inother words, it is determined whether any uplink beam 130 was determinedto be greater than minimum threshold 432 during the particular timeslot. If it is determined at step 802 that an uplink beam 130 wasselected during the particular time slot, the method proceeds to step810. However, if it is determined at step 802 that an uplink beam 130was not selected during the particular time slot, the method proceeds tostep 804. At step 804, it is determined whether a particular time periodor a particular number of time slots have passed since any uplink beam130 was last selected. If it is determined at step 804 that theparticular time period or number of time slots have not passed since anyuplink beam 130 was last selected, gain control module 488 may set thegain settings 490 equal to the baseline level for each beam receiver 112at step 806. On the other hand, if it is determined at step 804 that theparticular time period or number of time slots have passed since anyuplink beam 130 was last selected, gain control module 488 may increasethe baseline level for each beam receiver 112 at step 808 and set theseincreased gains as gain settings 490.

At step 810, it is determined whether the selected uplink beam 130received a burst from a mobile station 15 or noise from some othersource. In particular, gain control module 488 may analyze relevantsignaling information 754 that includes information about the signalsreceived during the particular time slot to determine whether a burstfrom a mobile station 15 was identified in that time slot. If it isdetermined at step 810 that the selected uplink beam 130 received aburst from a mobile station 15, gain control module 488 may set the gainsettings 490 equal to the baseline level for each beam receiver 112 atstep 812. On the other hand, if it is determined at step 810 that theselected uplink beam 130 did not receive a burst from a mobile station15 (rather, that selected uplink beam 130 received a burst of noise fromsome other source), gain control module 488 may set the gain settings490 equal to the baseline level for each beam receiver 112, exceptreducing the gain of the beam receiver 112 that received the selecteduplink beam 130, at step 814.

At step 816, the gain settings 490 determined at step 806, 808, 812 or814 are communicated from host processor 118 to receiving unit 108.These gain settings 490 are then used to set the gain of each beamreceiver 112 before or at the beginning of the next time slot. Thisprocess may be repeated to determine or update the gain settings 490 ofeach beam receiver 112 for determining fast decision beam selections440.

FIGS. 16 through 18 illustrate a smart decision beam selection systemand method in accordance with an embodiment of the present invention. Asshown in the embodiment of FIG. 16, a smart decision beam selectionmodule 410 comprises one or more smart decision algorithms 500, a buffer502, and a beam selection verification module 514. In one embodiment,smart decision algorithms 500 include a quality factor algorithm 504operable to determine a quality factor for one or more beams based onone or more inputs or parameters, including information from correlationmodule 400, signal strength module 402, storage module 406 and/or anyother suitable source of information. Buffer 502 is generally operableto receive and store quality factor selections made by quality factoralgorithm 504, and to determine a provisional beam selection 512 basedon the received and stored quality factor selections. Beam selectionverification module 514 is generally operable to determine whether toverify provisional beam selection 512 based on relevant signalinginformation 180 received from signaling information monitoring system106. If provisional beam selection 512 is verified by beam selectionverification module 514, the provisional beam selection 512 is selectedas the smart decision beam selection 506.

As discussed above with reference to FIG. 11, correlation module 400 maybe operable to correlate signal sequences received via one or moreuplink beams 150 with one or more known training sequences in order todetermine a correlation quality 508 for each of the beams. As discussedabove with reference to FIG. 12, signal strength module 402 may beoperable to determine a signal strength 438 associated with each uplinkbeam 130. In one embodiment, signal strength module 402 is operable todetermine the RSSI for each uplink beam 130.

Correlation qualities 508 and signal strengths 438 of each uplink beam130 may be communicated to smart decision beam selection module 410, aswell as to storage module 406. Storage module 406 includes a parameterdatabase 510 operable to store data regarding one or more inputs orparameters, such as correlation qualities 508 and signal strengths 438,for example. Storage module 406 may be operable to supply smart decisionbeam selection module 410 with data from parameter database 510 for usein determining smart decision beam selections 506.

In operation, quality factor algorithm 504 may be operable to receivecorrelation qualities 508 and signal strengths 438 from correlationmodule 400 and signal strength module 402, respectively, in real time,as well as stored data from parameter database 510, in order todetermine a quality factor for each uplink beam 130. Buffer 502 mayreceive one or more of the quality factors and determine provisionalbeam selection 512. Beam selection verification module 514 may thendetermine whether to verify provisional beam selection 512 based onrelevant signaling information 180. If provisional beam selection 512 isverified, it may be selected as the smart decision beam selection 506.This system is discussed in greater detail below with reference to FIG.17.

FIG. 17 illustrates relevant details and operation of smart decisionselection module 410 in accordance with one embodiment of the presentinvention. As discussed above, smart decision selection module 410 mayinclude quality factor algorithm 504, buffer 502, and beam selectionverification module 514. Quality factor algorithm 504 may include uplinkweights 520 and downlink weights 522. Uplink weights 520 may includeuplink parameter weights 524 and uplink history weights 526. Uplinkparameter weights 524 may include uplink correlation quality weight 528and uplink signal strength weight 530. Similarly downlink weights 522may include downlink parameter weights 532 and downlink history weights534. Downlink parameter weights 532 may include downlink correlationquality weight 536 and downlink signal strength weight 538.

In general, uplink weights 520 are used by uplink quality factoralgorithm 520 to determine uplink quality factors 550 corresponding toeach uplink beam 130 based on one or more inputs or parameters. Inparticular, parameter weights 524 are used to weight the significance ofeach parameter used in determining uplink quality factors 550. Uplinkcorrelation quality weight 528 and uplink signal strength weight 530 areused to weight the significance of the correlation quality and signalstrength, respectively, of each uplink beam 130 in determining uplinkquality factors 550. History weights 526 are used to weight thesignificance of each or one or more samples of the parameters. In someembodiments, history weights 526 are used to weight particulardeterminations, such as the correlation quality and signal strength ofeach uplink beam 130, based on the time slot or frame in which thedeterminations were made.

Similarly, downlink weights 522 may be used by downlink quality factoralgorithm 520 to determine downlink quality factors corresponding toeach uplink beam 130. It should be noted that although FIG. 17 focuseson the determination of uplink smart decision beam selection 506,downlink smart decision beam selection 507 may be determined in asimilar manner. However, in some embodiments, one or more downlinkweights 522 are different from their corresponding uplink weights 526,and thus the resulting downlink smart decision beam selection 507 may bedifferent than the uplink smart decision beam selection 506 determinedbased on the same inputs or parameters.

The following discussion relates to the operation of smart decision beamselection module 410 in determining uplink smart decision beam selection506. Uplink quality factor algorithm 540 may determine an uplink qualityfactor 550 for each uplink beam 130 based on one or more inputs,including correlation qualities 508 and signal strengths 438 for eachuplink beam 130. In particular, uplink quality factor algorithm 540 mayreceive correlation qualities 508 and signal strengths 438 determinedbased on a current or most recent time slot of each uplink beam 130,which may be referred to as time slot “t.” Uplink quality factoralgorithm 540 may also base its determination of each uplink qualityfactor 550 on information from parameter database 510, includingcorrelation qualities 508 and signal strengths 438 determined based onone or more prior time slots of each uplink beam 130, which may bereferred to as time slots “t-1,” “t-2,” and so on.

In one embodiment, uplink quality factor algorithm 540 determines theuplink quality factor (“QF”) 550 for each uplink beam 130 using thefollowing equation:QF(i)=a1*{b1*Corr _(—) Quality(i,t)+b2*Corr _(—) Quality(i,t-1)+b3*Corr_(—) Quality(i,t-2)+b4*Corr _(—) Quality(i,t-3)+ . . . +bn*Corr _(—)Quality(i,t-n-1)}+a2*{c1*Sig _(—) Strength(i,t)+c2*Sig _(—) Strength(i,t-1)++c3*Sig _(—)Strength(i,t-2)+c4*Sig _(—) Strength(i,t-3)+ . . . +ck*Sig _(—)Strength(i,t-k-1)}  (14)where:

-   “i” indicates the beam number,-   “t” indicates the time,-   Corr_Quality indicates the correlation quality of the beam,-   Sig_Strength indicates the signal strength of the beam, and-   a1+a2+ . . . =b1+b2+b3+b4+ . . . +bn=c1+c2+c3+c4+ . . . +ck=1

Smart decision beam selection module 410 may be operable to select thenumber of the beam having the highest uplink quality factor 550, shownin FIG. 17 as best quality beam number 552. In some embodiments, uplinkquality factor algorithm 540 is operable to determine a quality factor550 for each uplink beam 130, as well as a best quality beam number 552,in each time slot in each frame.

The best quality beam number 552 may be received by buffer 502, whichmay include a decision storage system 554 operable to store one or morepreviously determined best quality beam numbers 552. In someembodiments, decision storage system 554 may be operable to store one ormore previously determined best quality beam numbers 552 for each timeslot, or traffic channel, in the relevant frequency. Buffer 502 may beoperable to select a provisional beam selection 516 based on thereceived best quality beam number 552 as well as the previouslydetermined best quality beam numbers 552 stored in decision storagesystem 554. In one embodiment, decision storage system 554 maintains aset of best quality beam numbers 552 for each traffic channel anddetermines provisional beam selection 516 based on the beam numberoccurring most frequently in the set of best quality beam numbers 552.

In addition, buffer 502 may determine whether to select a provisionalbeam selection 516 based on whether the quality factor 550 of bestquality beam number 552 is sufficient. For example, buffer 502 maydetermine whether to select a provisional beam selection 516 based onwhether the quality factor 550 of best quality beam number 552 meets aparticular threshold value. In one embodiment, buffer 502 determineswhether to select a provisional beam selection 516 based on whether thequality factor 550 of best quality beam number 552 exceeds that of thenext best uplink beam 130 by a particular threshold value.

Beam selection verification module 516 may be operable to determinewhether to verify the provisional beam selection 516 selected by buffer502, and to select uplink smart decision beam selection 506 accordingly.In particular, beam selection verification module 516 may determinewhether to verify the provisional beam selection 516 based on relevantsignaling information 180 received from signaling information monitoringsystem 106, such as information regarding a new call beginning or anexisting call ending, or information regarding frequency hopping. Forexample, relevant signaling information 180 may comprise frequencyhopping information identifying one or more frequencies at which one ormore mobile stations 15 are expected to receive traffic signals inparticular frames or time slots. Beam selection verification module 516may use frequency hopping information in conjunction with theprovisional beam selection 516 selected by buffer 502 to select theappropriate uplink smart decision beam selection 506 for each frequency.

FIG. 18 illustrates a method of determining uplink smart decision beamselection 506 in accordance with an embodiment of the present invention.The method starts at step 570. At step 572, a correlation quality 508 isdetermined for each uplink beam 130. In particular, each correlationquality 508 may be determined by correlation module 400, as described ingreater detail below with reference to FIGS. 19 and 20. At step 574, asignal strength 438 is determined for each uplink beam 130. Inparticular, each signal strength 438 may be determined by signalstrength module 402. In addition, an average signal strength 438 may bedetermined for each uplink beam 130, such as discussed above withreference to FIG. 12.

At step 576, smart decision beam selection module executes uplinkquality factor algorithm 540 based on one or more inputs to determine aquality factor 550 for each uplink beam 130. In particular, uplinkquality factor algorithm 540 may use one or more uplink weights 520 toweight the significance of each input, such as discussed above withreference to FIG. 17. At step 578, the beam number of the beam havinghighest quality factor 550 is determined as best quality beam number552.

Best quality beam number 552 is communicated to buffer 502 at step 580.Buffer 502 determines an appropriate provisional beam selection 516based on the best quality beam number 552 received at step 580, as wellas previously received best quality beam numbers that are stored indecision storage system 554. In one embodiment, buffer 502 determinesprovisional beam selection 516 by selecting the most frequentlyoccurring beam number in buffer 502 for the appropriate time slot, ortraffic channel.

At step 584, it is determined whether provisional beam selection 516should be verified. In one embodiment, this determination is made bybeam selection verification module 514 based on relevant signalinginformation 180 received from signaling information monitoring system106. If it is determined that provisional beam selection 516 should beverified, provisional beam selection 516 is selected as uplink smartdecision beam selection 506 at step 586. If it is determined thatprovisional beam selection 516 should not be verified, beam selectionverification module 514 selects an appropriate uplink smart decisionbeam selection 506 based at least in part on relevant signalinginformation 180.

Whether or not provisional beam selection 516 is verified, the methodreturns to step 572 to continue sampling the correlation quality 508 andsignal strength 438 of each uplink beam 130 in order to repetitivelydetermine the quality factor 550 of each uplink beam 130. In thismanner, the method continues to communicate newly determined bestquality beam numbers 552 to buffer 502 which may in turn updateprovisional beam selection 516 if appropriate.

FIGS. 19 through 21 illustrate a system and method for determiningcorrelation qualities 508 of uplink beams 150 for use in determining aquality factor 550 of each uplink beam 130.

FIG. 19 illustrates correlation module 400 in accordance with anembodiment of the present invention. Correlation module 400 may includea training sequence database 600, a correlation algorithm 602, and aknown training sequence selection device 604. Training sequence database600 comprises one or more known training sequences 608. In particular,training sequence database 600 may include each known training sequence608 used in the appropriate communications standard. For example, in oneembodiment, each known training sequence 608 is one of the trainingsequences defined in GSM standard 05.02, after being modulated by MSK(Minimum Shift Keying) modulation. Known training sequence selectiondevice 604 is generally operable to determine one or more appropriatetraining sequences 605 from the group of known training sequences 608stored in training sequence database 600 with which each uplink beam 130should be correlated, as discussed below in greater detail.

Correlation module 400 is generally operable to correlate received beamsignals with known signals to determine the quality of the receivedsignals. In particular, correlation module 400 is operable to executecorrelation algorithm 602 to correlate a signal sequence 606 receivedvia each uplink beam 130 with one or more known training sequences 608in order to determine a correlation quality 508 of each uplink beam 130.Correlation algorithm 602 generally determines the similarity between aparticular signal sequence 606 and one or more known training sequences608. For example, correlation algorithm 602 may compare a signalsequence 606 with a known training sequences 608 to determine the numberof differences between the signal sequence 606 and the known trainingsequences 608. In other words, correlation algorithm 602 may determinethe number of errors in each signal sequence 606. In one embodiment,each known training sequence 608 comprises 26 bits, and thus each signalsequence may be found to contain anywhere from 0 to 26 errors whencompared with a particular known training sequences 608.

In some embodiments, correlation module 400 determines the correlationquality 508 for that uplink beam 130 by correlating the signal sequence606 received via each uplink beam 130 with each known training sequence608. In one such embodiment, the correlation quality 508 for each uplinkbeam 130 is the best correlation determined between the signal sequence606 received via that uplink beam 130 and each known training sequence608.

In other embodiments, correlation module 400 determines the correlationquality for each uplink beam 130 by correlating that uplink beam 130with one or more appropriate training sequences 605, rather than each ofthe known training sequences 608. The one or more appropriate trainingsequences 605 may be selected from the known training sequences 608 byknown training sequence selection device 604 based on relevant signalinginformation 180 received from signaling information monitoring system106. For example, known training sequence selection device 604 may beoperable to determine which mobile station 15 is communicating in aparticular time slot based on relevant signaling information 180, andselect the known training sequence 608 that is expected to be receivedfrom that mobile station 15 as the appropriate training sequence 605.

The correlation qualities 508 determined by correlation module 400 maybe used as input by beam selection modules 404 for use in selectingreceiving beam selections 126 and/or transmitting beam selections 124.In particular, correlation qualities 508 may be used as input by smartdecision beam selection module 410 in determining a quality factor 550of each uplink beam 130.

In one embodiment, correlation algorithm 602 may determine thecorrelation quality 508 of each uplink beam 130 as follows:

$\begin{matrix}{{\forall i},{{j\mspace{14mu}{{CORR}\left\lbrack {i,j} \right\rbrack}} = {\sum\limits_{n = 0}^{N}\;{Y_{i}\;\left( {n + j} \right)*{Training\_ s}^{H}\;\left( {N - n} \right)}}}} & (15)\end{matrix}$

$\begin{matrix}{{\forall i},{{j\mspace{14mu}{{SUM\_ CORR}\left\lbrack {i,j} \right\rbrack}} = {\sum\limits_{k = 0}^{K}\;{{CORR}\left\lbrack {i,{j + k}} \right\rbrack}}}} & (16)\end{matrix}$BEST _(—) CORR(i)=max_(j) {SUM _(—) CORR[i,j]}  (17)

Where:

-   Y_(i)(n) indicates the received signal from the receiver after it    was sampled;-   i indicates the number of the beam being analyzed;-   j indicates the length of the correlation window, which may be a    particular time period or number of frames;-   Training_s(n) indicates the expected known training sequence 608;-   N indicates the length of each training sequence;-   K indicates the maximum number of multi-paths considered by the    algorithm;-   CORR[i,j] indicates the correlation between the received signal    Y_(i)(n) and the expected known training sequence, Training_s(n);    and-   BEST_CORR(i) indicates the correlation quality 508 of the beam being    analyzed.

If the appropriate one of the known training sequences 608 is not known(for example, in an embodiment in which relevant signaling information180 is not used to determine one or more appropriate training sequences605), equations (15) through (17) may be repeated for each knowntraining sequence 608. The correlation quality 508, BEST_CORR(i), of theuplink beam 130 being analyzed may then be determined as follows:BEST _(—) CORR[i,num]=max_(j) {SUM _(—) CORR[i,j]}  (18)BEST _(—) CORR(i)=max_(num) {BEST _(—) CORR[i,num]}  (19)

In some embodiments, BEST_CORR(i) for each uplink beam 130 may be usedby uplink quality factor algorithm 540 as the Corr_Quality parameter inequation (14) above.

FIG. 20 illustrates a method of determining a correlation quality 508for a particular uplink beam 130 by correlating the signal sequence 606communicated by the uplink beam 130 with each known training sequence608. At step 630, the method starts. At step 632, the uplink beam 130 isreceived by correlation module 400. In one embodiment, uplink beam 130is received from one of the receiving units 108. At step 634,correlation module 400 correlates signal sequence 606 with each knowntraining sequence 608 to determine a set of correlations including acorrelation for each known training sequence 608. In particular,correlation module 400 may execute at least a portion of correlationalgorithm 602 to determine the correlation between signal sequence 606and each known training sequence 608. At step 636, correlation module400 may determine the correlation quality 508 of uplink beam 130 bydetermining the best correlation in the set of correlations. The methodmay then return to step 632 to receive another signal sequence 606 viauplink beam 130. In one embodiment, a new correlation quality 508 isdetermined for the signal sequence 606 received via uplink beam 130 ineach time slot during an ongoing call. It should be understood that themethod illustrated in FIG. 20 may be used to determine a correlationquality 508 for each uplink beam 130.

FIG. 21 illustrates a method of determining a correlation quality 508for a particular uplink beam 130 by correlating the signal sequence 606communicated by the uplink beam 130 with one appropriate known trainingsequence 608. At step 650, the method starts. At step 652, the uplinkbeam 130 is received by correlation module 400. At step 654, knowntraining sequence selection device 604 may select from the knowntraining sequences 608 an appropriate training sequence 605 with whichto correlate signal sequence 606. In one embodiment, known trainingsequence selection device 604 selects appropriate training sequence 605based on relevant signaling information 180 received from signalinginformation monitoring system 106. At step 656, correlation module 400correlates signal sequence 606 with appropriate training sequence 605selected at step 654 to determine the correlation quality 508 of uplinkbeam 130. In particular, correlation module 400 may execute at least aportion of correlation algorithm 602 to determine the correlationquality 508 of uplink beam 130. The method may then return to step 652to receive another signal sequence 606 via uplink beam 130. In oneembodiment, a new correlation quality 508 is determined for the signalsequence 606 received via uplink beam 130 in each time slot during anongoing call. It should be understood that the method illustrated inFIG. 21 may be used to determine a correlation quality 508 for eachuplink beam 130.

The method of FIG. 21 may be used to decrease processing time since thesignal sequence 606 in each uplink beam 130 is correlated with one knowntraining sequence 608 rather than each known training sequence 608. Inparticular, the use of relevant signaling information 180 to determineone or more appropriate training sequences 605 decreases the processingtime required to determine the correlation quality 508 of each uplinkbeam 130.

FIGS. 22 and 23 illustrate a system and method for determining whetherto select the beam selection determinations made by fast decision beamselection module 408 or smart decision beam selection module 410 inaccordance with an embodiment of the present inventions.

FIG. 22 illustrates a system for determining whether to use fastdecision beam selection module 408, smart decision beam selection module410, or neither for selecting an appropriate one or more narrow beams 34for receiving signals from and/or transmitting signals to one or moremobile station 15. Processing module 62 comprises fast decision beamselection module 408, smart decision beam selection module 410, andfast/smart selection module 416. As discussed above with reference toFIG. 12, fast decision beam selection module 408 is operable todetermine fast decision beam selections 440 substantially in real timebased on the current frame of signals received via one or more beams.And as discussed above with reference to FIGS. 16 and 17, smart decisionbeam selection module 410 is operable to determine smart decision beamselections 620, such as uplink and downlink smart decision beamselections 506 and 507, based on both current and previous frames ofsuch signals. In some embodiments, smart antenna apparatus 16 switchesto the smart decision beam selections 620 determined by smart decisionbeam selection module 410 in the frame following the current frame.Thus, in some embodiments, there may be a delay of one or more framesbetween the frame at which uplink signals are received by smart antennaapparatus 16 and the frame at which smart antenna apparatus 16 switchesto the appropriate smart decision beam selections 620. In addition, insome embodiments, since smart decision beam selection module 410determines smart decision beam selections based on both current andprevious frames of signal data, smart decision beam selections 620 areonly determined when smart decision beam selection module 410 hasinformation regarding previous frames of the signals being analyzed.

Fast/smart selection module 416 is generally operable to determinewhether to select beam selection determinations made by fast decisionbeam selection module 408, smart decision beam selection module 410, orneither for one or more time slots or frames. Generally, fast decisionbeam selections 440 are used during the initiation of a call or othercommunication to or from a mobile station 15 since smart antennaapparatus 16 has little or no prior data regarding the mobile linkconnection with mobile station 15, and smart decision beam selections620 are used after the call has been established and smart antennaapparatus 16 has data regarding the location of mobile station 15 fromsignals received in prior frames. In some embodiments, fast decisionbeam selections 440 are used for signals received from mobile stations15 in a random access channel (RACH), such as access request signals. Inaddition, fast decision beam selections 440 may be used for one or moreof initial frames after mobile station 15 has switched to the trafficchannel which is used during at least a first portion of the call. Inone embodiment, fast decision beam selections 440 are used for RACHsignals and for the first time slot after mobile station 15 switches toa traffic channel to support a call, and smart decision beam selections620 are used for subsequent time slots during the call.

Fast/smart selection module 416 may be a discrete module operable toperform the determine whether to use fast decision beam selections 440or smart decision beam selections 620 as discussed above, or it may be adistributed system distributed among any number of components of smartantenna apparatus 16, such as fast decision beam selection module 408,smart decision beam selection module 410. For example, in oneembodiment, smart decision beam selection module 410 is operable todetermine whether to use the smart decision beam selection 620 or thefast decision beam selection 440 for a particular time slot.

The beam selected by fast/smart selection module 416, which is generallya fast decision beam selection 440 or a smart decision beam selection620, may be referred to as a fast/smart beam selection 622. In someembodiments, fast/smart beam selection 622 is the beam selected for oneof the frequencies used by base station transceiver 24. Thus, smartantenna apparatus 16 may determine a fast/smart beam selection 622 foreach frequency used by base station transceiver 24. In some embodiments,fast/smart beam selections 622 are further processed by centralprocessing unit 118 before being selected as transmitting beam selection124 or receiving beam selection 126.

FIG. 23 illustrates a method using fast decision beam selections 440 andsmart decision beam selections 620 in smart antenna system 14. At step630, a random access (RACH) burst is communicated by a mobile station 15and received by receiving system 100 in a particular time slot of acurrent frame. The burst is communicated to processing module 62 at step632. At step 634, fast decision beam selection module 408 determines afast decision beam selection 440 substantially in real time based on theburst received in the particular time slot of the current frame. At step636, the burst is communicated to base station transceiver 24 via thebeam selected as fast decision beam selection 440.

At step 638, mobile station 15 switches to a traffic channel forcommunicating voice or other data signals during the call. Inparticular, mobile station 15 may switch to a particular traffic channelassigned by base station system 12. At step 640, mobile station 15transmits traffic signals in a first frame of the assigned trafficchannel, which are received by receiving system 100 and communicated toprocessing module 62. At step 642, fast decision beam selection module408 determines a fast decision beam selection 440 based on the trafficsignals (which may include a training sequence) received in the firstframe. In particular, fast decision beam selection module 408 maydetermines fast decision beam selection 440 substantially in real time.At step 644, smart decision beam selection module 410 determines a smartdecision beam selection 620 based on the traffic signals received in thefirst frame. At step 646, the traffic signals received in the firstframe are communicated to base station transceiver 24 via the beamselected as fast decision beam selection 440. The determination of smartdecision beam selection 620 at step 644 may not be completed until afterthe traffic signals are communicated to base station transceiver 24 atstep 646.

At step 648, mobile station 15 transmits additional traffic signals in asecond frame of the assigned traffic channel, which are received byreceiving system 100 and communicated to processing module 62. At step650, fast decision beam selection module 408 determines a fast decisionbeam selection 440 based on the traffic signals received in the secondframe. At step 652, smart decision beam selection module 410 determinesa smart decision beam selections 620 based on the traffic signalsreceived in the second frame along with signals received in one or moreframes prior to the second frame (which may or may not include the firstframe). At step 654, it is determined whether the smart decision beamselection 620 determined at step 644 meets a particular criteria. Forexample, in one embodiment it is determined whether the quality of smartdecision beam selection 620 determined at step 644 meets a particularthreshold. If it is determined that the smart decision beam selection620 determined at step 644 does meet the particular criteria, at step656 the traffic signals received in the second frame are communicated tobase station transceiver 24 via the beam selected as smart decision beamselection 620 at step 644. If it is determined that the smart decisionbeam selection 620 determined at step 644 does not meet the particularcriteria, at step 658 the traffic signals received in the second frameare communicated to base station transceiver 24 via the beam selected asfast decision beam selection 440 at step 650.

Steps 648 through 658 may be repeated one or more times. In particular,steps 648 through 658 may be repeated in order to continually updatesmart decision beam selection 620 during the remainder of the call. Inaddition, in some situations, steps 640 through 646 may be repeated oneor more times before using a smart decision beam selection 620. Inparticular, steps 640 through 646 may be repeated one or more timesuntil smart decision beam selection module 410 has sufficient data todetermine an adequate smart decision beam selection 620.

Smart antenna system 14 may provide a number of advantages. For example,in some embodiments, smart antenna apparatus 16 may be coupled to a newor existing base station transceiver as an add-on or applique withouthaving to modify, alter, or reconfigure the base station transceiver orany other component of the base station system, such as base stationcontrollers. Thus, the cost and labor of modifying or altering basestation system 12 and/or dealing or negotiating with the manufacturer ofthe components of base station system 12, such as base stationtransceiver 24 and base station controller 26, is eliminated in someembodiments. Moreover, smart antenna apparatus 16 may be compatible withbase station transceivers produced by a variety of manufacturers. Forexample, smart antenna apparatus 16 may be compatible with all basestation transceivers using standard base station transceiver interfaces.For at least the reasons discussed above, the installation costs ofsmart antenna apparatus 16 are reduced as compared with traditionalsmart antenna systems. Moreover, the operating costs of smart antennaapparatus 16 are reduced as compared with traditional smart antennasystems.

In addition, the presence and operation of smart antenna apparatus 16may be transparent to the base station system, including the basestation transceiver. In other words, smart antenna apparatus 16 causeslittle delay (and in some embodiments, no delay) in the reception andtransmission of radio signals to and from the base station transceiver.Thus, smart antenna apparatus 16 may operate without affecting thetiming of the cellular network or any mobile stations.

In addition, the beam selection systems and methods provided by smartantenna apparatus 16 as described above with reference to FIGS. 11through 23 may provide a number of advantages. For example, smartantenna apparatus 16 may reduce the interference, such as multi-path andco-channel interference, associated with uplink signals received by anew or existing base station transceiver. In addition, smart antennaapparatus 16 may reduce the interference associated with downlinksignals received by mobile stations. Thus, smart antenna apparatus 16may increase the effective capacity and improve the overall performanceof the base station transceiver without requiring any modifications tothe base station transceiver. For example, since using narrow beamsgenerally increases the range (or coverage) of effective reception andtransmission as compared with wide beams, smart antenna apparatus 16 mayincrease the range of the base station transceiver to which it is added.Moreover, smart antenna apparatus 16 may improve the signal-to-noiseratio (SNR) of transmitted and/or received signals, and thus increasesthe data rate which may be transmitted and/or received by the basestation transceiver.

In some embodiments, smart antenna apparatus 16 may reduce theinterference associated with received and/or transmitted signals betterthen traditional smart antenna systems. As a result, smart antennaapparatus 16 may provide increased capacity, coverage, and efficiency ascompared with traditional smart antenna systems.

Although embodiments of the invention and their advantages are describedin detail, a person of ordinary skill in the art could make variousalterations, additions, and omissions without departing from the spiritand scope of the present invention as defined by the appended claims.

1. A method of synchronizing a smart antenna apparatus, comprising:receiving at the smart antenna apparatus control signals beingcommunicated from a base station transceiver to one or more mobilestations via an antenna unit, the control signals being operable to beused to synchronize the mobile stations with the base stationtransceiver; and executing one or more synchronization algorithms usingthe control signals received by the smart antenna apparatus as input tosynchronize the smart antenna apparatus with the base stationtransceiver.
 2. The method of claim 1, wherein the control signals arereceived at the smart antenna apparatus from the base stationtransceiver via one or more radio signal wires.
 3. The method of claim1, wherein the control signals are received at the smart antennaapparatus from the base station transceiver without affecting thecommunication of the control signals from the base station transceiverto the one or more mobile stations.
 4. The method of claim 1, whereinreceiving the control signals comprises splitting a path of the controlsignals being communicated from a base station transceiver into a firstpath for synchronizing the mobile stations with the base stationtransceiver and a second path for synchronizing the smart antennaapparatus with the base station transceiver.
 5. The method of claim 1,wherein the control signals are communicated from the base stationtransceiver at a first frequency; and wherein the method furthercomprises converting the control signals from the first frequency to asecond frequency before the control signals are used as input tosynchronize the smart antenna apparatus with the base stationtransceiver.
 6. The method of claim 5, wherein the first frequency is adownlink control frequency and the second frequency is a correspondinguplink frequency.
 7. The method of claim 5, wherein the first frequencyis not operable to be received by the smart antenna apparatus.
 8. Themethod of claim 5, wherein the control signals are converted from thefirst frequency to the second frequency by mixing the controls signalswith a conversion signal.
 9. The method of claim 8, wherein theconversion signal has a frequency of approximately 45 MHz.
 10. Themethod of claim 1, further comprising converting the control signalsreceived by the smart antenna apparatus from digital to analog beforeexecuting the one or more synchronization algorithms.
 11. The method ofclaim 1, wherein the synchronization algorithms are operable tosynchronize the smart antenna apparatus with the base stationtransceiver in time within an accuracy of one bit.
 12. The method ofclaim 1, wherein the synchronization algorithms are operable tosynchronize the smart antenna apparatus with the base stationtransceiver in time within an accuracy of one quarter of one GSM bit.13. The method of claim 1, wherein the synchronization algorithms areoperable to synchronize the smart antenna apparatus with the basestation transceiver in frequency within an accuracy of 50 Hz.
 14. Themethod of claim 1, wherein: the control signals are communicated in acontrol channel and include synchronization bursts; and executing theone or more algorithms comprises executing a time synchronizationalgorithm to use one or more of the synchronization bursts tosynchronize the smart antenna apparatus with the base stationtransceiver in time.
 15. The method of claim 1, wherein: the controlsignals are communicated in a control channel and include frequencycorrection bursts; and executing the one or more algorithms comprisesexecuting a frequency synchronization algorithm to use one or more ofthe frequency correction bursts to synchronize the smart antennaapparatus with the base station transceiver in frequency.
 16. The methodof claim 1, wherein: the control signals are communicated in a controlchannel within a control frequency and include one or moresynchronization bursts and one or more frequency correction bursts; andexecuting the one or more algorithms comprises executing a coarse timingsynchronization algorithm, a frame synchronization algorithm, and one ormore fine tuning algorithms.
 17. A method of synchronizing a smartantenna apparatus, comprising: receiving at a smart antenna apparatuscontrol signals being communicated from a base station transceiver toone or more mobile stations via an antenna unit; wherein the controlsignals are communicated from the base station transceiver at a downlinkcontrol frequency; wherein the control signals are operable to be usedto synchronize the mobile stations with the base station transceiver;and wherein the control signals are received at the smart antennaapparatus from the base station transceiver via one or more radio signalwires without affecting the communication of the control signals fromthe base station transceiver to the one or more mobile stations;converting the control signals from the downlink control frequency to acorresponding uplink frequency; and executing one or moresynchronization algorithms using the control signals as input tosynchronize the smart antenna apparatus with the base stationtransceiver.
 18. A smart antenna apparatus comprising: a signal receiveroperable to receive one or more control signals being communicated froma base station transceiver to one or more mobile stations via an antennaunit, the control signals operable to be used to synchronize the mobilestations with the base station transceiver; and a processor operable toexecute one or more synchronization algorithms using the control signalsreceived at the signal receiver as input to synchronize the smartantenna apparatus with the base station transceiver.
 19. The apparatusof claim 18, further comprising at least one radio wire input operableto receive a radio signal wire via which the control signals arecommunicated from the base station transceiver.
 20. The apparatus ofclaim 18, further comprising a signal splitting device operable to splita path of the control signals being communicated from a base stationtransceiver into a first path to the antenna unit and a second path tothe signal receiver.
 21. The apparatus of claim 18, wherein the signalsplitting device is operable to split the path of the control signalswithout affecting the communication of the control signals from the basestation transceiver to the one or more mobile stations.
 22. Theapparatus of claim 18, further comprising a mixing device operable toconvert the control signals from a first frequency to a second frequencybefore the control signals are received by the signal receiver.
 23. Theapparatus of claim 22, wherein the first frequency is a downlink controlfrequency and the second frequency is a corresponding uplink frequency.24. The apparatus of claim 18, further comprising a sampling deviceoperable to convert the control signals received at the signal receiverfrom digital to analog for use by the processor.
 25. The apparatus ofclaim 18, wherein the processor is operable to execute the one or moresynchronization algorithms to synchronize the smart antenna apparatuswith the base station transceiver in time within an accuracy of one bit.26. The apparatus of claim 18, wherein the processor is operable toexecute the one or more synchronization algorithms to synchronize thesmart antenna apparatus with the base station transceiver in time withinan accuracy of one quarter of one GSM bit.
 27. The apparatus of claim18, wherein the processor is operable to execute the one or moresynchronization algorithms to synchronize the smart antenna apparatuswith the base station transceiver in frequency within an accuracy of 50Hz.
 28. The apparatus of claim 18, wherein: the control signals arecommunicated in a control channel and include synchronization bursts;and the processor is operable to execute a time synchronizationalgorithm to use one or more of the synchronization bursts tosynchronize the smart antenna apparatus with the base stationtransceiver in time.
 29. The apparatus of claim 18, wherein: the controlsignals are communicated in a control channel and include frequencycorrection bursts; and the processor is operable to execute a frequencysynchronization algorithm to use one or more of the frequency correctionbursts to synchronize the smart antenna apparatus with the base stationtransceiver in frequency.
 30. The apparatus of claim 18, wherein: thecontrol signals are communicated in a control channel within a controlfrequency and include one or more synchronization bursts and one or morefrequency correction bursts; and the processor is operable to execute acoarse timing synchronization algorithm, a frame synchronizationalgorithm, and one or more fine tuning algorithms.
 31. A smart antennaapparatus comprising: a signal splitting device operable to: receivecontrol signals transmitted from a base station transceiver via a radiosignal wire; and split the control signals communicated via the radiosignal wire into a first path for synchronizing one or more mobilestations with the base station transceiver and a second path forsynchronizing the smart antenna apparatus with the base stationtransceiver; wherein the signal splitting device is operable to splitthe control signals without affecting the communication of the controlsignals from the base station transceiver to the one or more mobilestations; a mixing device operable to convert the control signalscommunicated via the second path from a downlink control frequency to acorresponding uplink frequency; and a processor operable to execute oneor more synchronization algorithms using the control signals as input tosynchronize the smart antenna apparatus with the base stationtransceiver.